| 1 |
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| 2 | #ifndef _LINUX_XARRAY_H
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| 3 | #define _LINUX_XARRAY_H
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| 4 | |
| 5 | * eXtensible Arrays
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| 6 | * Copyright (c) 2017 Microsoft Corporation
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| 7 | * Author: Matthew Wilcox <[email protected]>
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| 8 | *
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| 9 | * See Documentation/core-api/xarray.rst for how to use the XArray.
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| 10 |
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| 11 |
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| 12 | #include <linux/bitmap.h>
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| 13 | #include <linux/bug.h>
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| 14 | #include <linux/compiler.h>
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| 15 | #include <linux/gfp.h>
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| 16 | #include <linux/kconfig.h>
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| 17 | #include <linux/kernel.h>
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| 18 | #include <linux/rcupdate.h>
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| 19 | #include <linux/sched/mm.h>
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| 20 | #include <linux/spinlock.h>
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| 21 | #include <linux/types.h>
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| 22 |
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| 23 | |
| 24 | * The bottom two bits of the entry determine how the XArray interprets
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| 25 | * the contents:
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| 26 | *
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| 27 | * 00: Pointer entry
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| 28 | * 10: Internal entry
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| 29 | * x1: Value entry or tagged pointer
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| 30 | *
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| 31 | * Attempting to store internal entries in the XArray is a bug.
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| 32 | *
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| 33 | * Most internal entries are pointers to the next node in the tree.
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| 34 | * The following internal entries have a special meaning:
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| 35 | *
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| 36 | * 0-62: Sibling entries
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| 37 | * 256: Retry entry
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| 38 | * 257: Zero entry
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| 39 | *
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| 40 | * Errors are also represented as internal entries, but use the negative
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| 41 | * space (-4094 to -2). They're never stored in the slots array; only
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| 42 | * returned by the normal API.
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| 43 |
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| 44 |
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| 45 | #define BITS_PER_XA_VALUE (BITS_PER_LONG - 1)
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| 46 |
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| 47 | |
| 48 | * xa_mk_value() - Create an XArray entry from an integer.
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| 49 | * @v: Value to store in XArray.
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| 50 | *
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| 51 | * Context: Any context.
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| 52 | * Return: An entry suitable for storing in the XArray.
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| 53 |
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| 54 | static inline void *xa_mk_value(unsigned long v)
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| 55 | {
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| 56 | WARN_ON((long)v < 0);
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| 57 | return (void *)((v << 1) | 1);
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| 58 | }
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| 59 |
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| 60 | |
| 61 | * xa_to_value() - Get value stored in an XArray entry.
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| 62 | * @entry: XArray entry.
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| 63 | *
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| 64 | * Context: Any context.
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| 65 | * Return: The value stored in the XArray entry.
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| 66 |
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| 67 | static inline unsigned long xa_to_value(const void *entry)
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| 68 | {
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| 69 | return (unsigned long)entry >> 1;
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| 70 | }
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| 71 |
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| 72 | |
| 73 | * xa_is_value() - Determine if an entry is a value.
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| 74 | * @entry: XArray entry.
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| 75 | *
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| 76 | * Context: Any context.
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| 77 | * Return: True if the entry is a value, false if it is a pointer.
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| 78 |
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| 79 | static inline bool xa_is_value(const void *entry)
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| 80 | {
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| 81 | return (unsigned long)entry & 1;
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| 82 | }
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| 83 |
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| 84 | |
| 85 | * xa_tag_pointer() - Create an XArray entry for a tagged pointer.
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| 86 | * @p: Plain pointer.
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| 87 | * @tag: Tag value (0, 1 or 3).
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| 88 | *
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| 89 | * If the user of the XArray prefers, they can tag their pointers instead
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| 90 | * of storing value entries. Three tags are available (0, 1 and 3).
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| 91 | * These are distinct from the xa_mark_t as they are not replicated up
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| 92 | * through the array and cannot be searched for.
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| 93 | *
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| 94 | * Context: Any context.
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| 95 | * Return: An XArray entry.
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| 96 |
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| 97 | static inline void *xa_tag_pointer(void *p, unsigned long tag)
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| 98 | {
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| 99 | return (void *)((unsigned long)p | tag);
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| 100 | }
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| 101 |
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| 102 | |
| 103 | * xa_untag_pointer() - Turn an XArray entry into a plain pointer.
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| 104 | * @entry: XArray entry.
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| 105 | *
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| 106 | * If you have stored a tagged pointer in the XArray, call this function
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| 107 | * to get the untagged version of the pointer.
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| 108 | *
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| 109 | * Context: Any context.
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| 110 | * Return: A pointer.
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| 111 |
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| 112 | static inline void *xa_untag_pointer(void *entry)
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| 113 | {
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| 114 | return (void *)((unsigned long)entry & ~3UL);
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| 115 | }
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| 116 |
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| 117 | |
| 118 | * xa_pointer_tag() - Get the tag stored in an XArray entry.
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| 119 | * @entry: XArray entry.
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| 120 | *
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| 121 | * If you have stored a tagged pointer in the XArray, call this function
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| 122 | * to get the tag of that pointer.
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| 123 | *
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| 124 | * Context: Any context.
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| 125 | * Return: A tag.
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| 126 |
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| 127 | static inline unsigned int xa_pointer_tag(void *entry)
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| 128 | {
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| 129 | return (unsigned long)entry & 3UL;
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| 130 | }
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| 131 |
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| 132 | |
| 133 | * xa_mk_internal() - Create an internal entry.
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| 134 | * @v: Value to turn into an internal entry.
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| 135 | *
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| 136 | * Internal entries are used for a number of purposes. Entries 0-255 are
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| 137 | * used for sibling entries (only 0-62 are used by the current code). 256
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| 138 | * is used for the retry entry. 257 is used for the reserved / zero entry.
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| 139 | * Negative internal entries are used to represent errnos. Node pointers
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| 140 | * are also tagged as internal entries in some situations.
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| 141 | *
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| 142 | * Context: Any context.
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| 143 | * Return: An XArray internal entry corresponding to this value.
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| 144 |
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| 145 | static inline void *xa_mk_internal(unsigned long v)
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| 146 | {
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| 147 | return (void *)((v << 2) | 2);
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| 148 | }
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| 149 |
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| 150 | |
| 151 | * xa_to_internal() - Extract the value from an internal entry.
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| 152 | * @entry: XArray entry.
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| 153 | *
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| 154 | * Context: Any context.
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| 155 | * Return: The value which was stored in the internal entry.
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| 156 |
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| 157 | static inline unsigned long xa_to_internal(const void *entry)
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| 158 | {
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| 159 | return (unsigned long)entry >> 2;
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| 160 | }
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| 161 |
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| 162 | |
| 163 | * xa_is_internal() - Is the entry an internal entry?
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| 164 | * @entry: XArray entry.
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| 165 | *
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| 166 | * Context: Any context.
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| 167 | * Return: %true if the entry is an internal entry.
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| 168 |
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| 169 | static inline bool xa_is_internal(const void *entry)
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| 170 | {
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| 171 | return ((unsigned long)entry & 3) == 2;
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| 172 | }
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| 173 |
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| 174 | #define XA_ZERO_ENTRY xa_mk_internal(257)
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| 175 |
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| 176 | |
| 177 | * xa_is_zero() - Is the entry a zero entry?
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| 178 | * @entry: Entry retrieved from the XArray
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| 179 | *
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| 180 | * The normal API will return NULL as the contents of a slot containing
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| 181 | * a zero entry. You can only see zero entries by using the advanced API.
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| 182 | *
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| 183 | * Return: %true if the entry is a zero entry.
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| 184 |
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| 185 | static inline bool xa_is_zero(const void *entry)
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| 186 | {
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| 187 | return unlikely(entry == XA_ZERO_ENTRY);
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| 188 | }
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| 189 |
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| 190 | |
| 191 | * xa_is_err() - Report whether an XArray operation returned an error
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| 192 | * @entry: Result from calling an XArray function
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| 193 | *
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| 194 | * If an XArray operation cannot complete an operation, it will return
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| 195 | * a special value indicating an error. This function tells you
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| 196 | * whether an error occurred; xa_err() tells you which error occurred.
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| 197 | *
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| 198 | * Context: Any context.
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| 199 | * Return: %true if the entry indicates an error.
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| 200 |
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| 201 | static inline bool xa_is_err(const void *entry)
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| 202 | {
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| 203 | return unlikely(xa_is_internal(entry) &&
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| 204 | entry >= xa_mk_internal(-MAX_ERRNO));
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| 205 | }
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| 206 |
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| 207 | |
| 208 | * xa_err() - Turn an XArray result into an errno.
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| 209 | * @entry: Result from calling an XArray function.
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| 210 | *
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| 211 | * If an XArray operation cannot complete an operation, it will return
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| 212 | * a special pointer value which encodes an errno. This function extracts
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| 213 | * the errno from the pointer value, or returns 0 if the pointer does not
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| 214 | * represent an errno.
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| 215 | *
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| 216 | * Context: Any context.
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| 217 | * Return: A negative errno or 0.
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| 218 |
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| 219 | static inline int xa_err(void *entry)
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| 220 | {
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| 221 |
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| 222 | if (xa_is_err(entry))
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| 223 | return (long)entry >> 2;
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| 224 | return 0;
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| 225 | }
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| 226 |
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| 227 | |
| 228 | * struct xa_limit - Represents a range of IDs.
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| 229 | * @min: The lowest ID to allocate (inclusive).
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| 230 | * @max: The maximum ID to allocate (inclusive).
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| 231 | *
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| 232 | * This structure is used either directly or via the XA_LIMIT() macro
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| 233 | * to communicate the range of IDs that are valid for allocation.
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| 234 | * Three common ranges are predefined for you:
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| 235 | * * xa_limit_32b - [0 - UINT_MAX]
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| 236 | * * xa_limit_31b - [0 - INT_MAX]
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| 237 | * * xa_limit_16b - [0 - USHRT_MAX]
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| 238 |
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| 239 | struct xa_limit {
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| 240 | u32 max;
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| 241 | u32 min;
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| 242 | };
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| 243 |
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| 244 | #define XA_LIMIT(_min, _max) (struct xa_limit) { .min = _min, .max = _max }
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| 245 |
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| 246 | #define xa_limit_32b XA_LIMIT(0, UINT_MAX)
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| 247 | #define xa_limit_31b XA_LIMIT(0, INT_MAX)
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| 248 | #define xa_limit_16b XA_LIMIT(0, USHRT_MAX)
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| 249 |
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| 250 | typedef unsigned __bitwise xa_mark_t;
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| 251 | #define XA_MARK_0 ((__force xa_mark_t)0U)
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| 252 | #define XA_MARK_1 ((__force xa_mark_t)1U)
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| 253 | #define XA_MARK_2 ((__force xa_mark_t)2U)
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| 254 | #define XA_PRESENT ((__force xa_mark_t)8U)
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| 255 | #define XA_MARK_MAX XA_MARK_2
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| 256 | #define XA_FREE_MARK XA_MARK_0
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| 257 |
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| 258 | enum xa_lock_type {
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| 259 | XA_LOCK_IRQ = 1,
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| 260 | XA_LOCK_BH = 2,
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| 261 | };
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| 262 |
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| 263 | |
| 264 | * Values for xa_flags. The radix tree stores its GFP flags in the xa_flags,
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| 265 | * and we remain compatible with that.
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| 266 |
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| 267 | #define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ)
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| 268 | #define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH)
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| 269 | #define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U)
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| 270 | #define XA_FLAGS_ZERO_BUSY ((__force gfp_t)8U)
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| 271 | #define XA_FLAGS_ALLOC_WRAPPED ((__force gfp_t)16U)
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| 272 | #define XA_FLAGS_ACCOUNT ((__force gfp_t)32U)
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| 273 | #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \
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| 274 | (__force unsigned)(mark)))
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| 275 |
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| 276 |
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| 277 | #define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK))
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| 278 | #define XA_FLAGS_ALLOC1 (XA_FLAGS_TRACK_FREE | XA_FLAGS_ZERO_BUSY)
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| 279 |
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| 280 | |
| 281 | * struct xarray - The anchor of the XArray.
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| 282 | * @xa_lock: Lock that protects the contents of the XArray.
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| 283 | *
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| 284 | * To use the xarray, define it statically or embed it in your data structure.
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| 285 | * It is a very small data structure, so it does not usually make sense to
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| 286 | * allocate it separately and keep a pointer to it in your data structure.
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| 287 | *
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| 288 | * You may use the xa_lock to protect your own data structures as well.
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| 289 |
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| 290 | |
| 291 | * If all of the entries in the array are NULL, @xa_head is a NULL pointer.
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| 292 | * If the only non-NULL entry in the array is at index 0, @xa_head is that
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| 293 | * entry. If any other entry in the array is non-NULL, @xa_head points
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| 294 | * to an @xa_node.
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| 295 |
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| 296 | struct xarray {
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| 297 | spinlock_t xa_lock;
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| 298 |
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| 299 | gfp_t xa_flags;
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| 300 | void __rcu * xa_head;
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| 301 | };
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| 302 |
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| 303 | #define XARRAY_INIT(name, flags) { \
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| 304 | .xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \
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| 305 | .xa_flags = flags, \
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| 306 | .xa_head = NULL, \
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| 307 | }
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| 308 |
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| 309 | |
| 310 | * DEFINE_XARRAY_FLAGS() - Define an XArray with custom flags.
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| 311 | * @name: A string that names your XArray.
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| 312 | * @flags: XA_FLAG values.
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| 313 | *
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| 314 | * This is intended for file scope definitions of XArrays. It declares
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| 315 | * and initialises an empty XArray with the chosen name and flags. It is
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| 316 | * equivalent to calling xa_init_flags() on the array, but it does the
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| 317 | * initialisation at compiletime instead of runtime.
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| 318 |
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| 319 | #define DEFINE_XARRAY_FLAGS(name, flags) \
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| 320 | struct xarray name = XARRAY_INIT(name, flags)
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| 321 |
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| 322 | |
| 323 | * DEFINE_XARRAY() - Define an XArray.
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| 324 | * @name: A string that names your XArray.
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| 325 | *
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| 326 | * This is intended for file scope definitions of XArrays. It declares
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| 327 | * and initialises an empty XArray with the chosen name. It is equivalent
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| 328 | * to calling xa_init() on the array, but it does the initialisation at
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| 329 | * compiletime instead of runtime.
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| 330 |
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| 331 | #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0)
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| 332 |
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| 333 | |
| 334 | * DEFINE_XARRAY_ALLOC() - Define an XArray which allocates IDs starting at 0.
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| 335 | * @name: A string that names your XArray.
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| 336 | *
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| 337 | * This is intended for file scope definitions of allocating XArrays.
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| 338 | * See also DEFINE_XARRAY().
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| 339 |
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| 340 | #define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC)
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| 341 |
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| 342 | |
| 343 | * DEFINE_XARRAY_ALLOC1() - Define an XArray which allocates IDs starting at 1.
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| 344 | * @name: A string that names your XArray.
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| 345 | *
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| 346 | * This is intended for file scope definitions of allocating XArrays.
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| 347 | * See also DEFINE_XARRAY().
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| 348 |
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| 349 | #define DEFINE_XARRAY_ALLOC1(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC1)
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| 350 |
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| 351 | void *xa_load(struct xarray *, unsigned long index);
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| 352 | void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
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| 353 | void *xa_erase(struct xarray *, unsigned long index);
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| 354 | void *xa_store_range(struct xarray *, unsigned long first, unsigned long last,
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| 355 | void *entry, gfp_t);
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| 356 | bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t);
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| 357 | void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t);
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| 358 | void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t);
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| 359 | void *xa_find(struct xarray *xa, unsigned long *index,
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| 360 | unsigned long max, xa_mark_t) __attribute__((nonnull(2)));
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| 361 | void *xa_find_after(struct xarray *xa, unsigned long *index,
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| 362 | unsigned long max, xa_mark_t) __attribute__((nonnull(2)));
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| 363 | unsigned int xa_extract(struct xarray *, void **dst, unsigned long start,
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| 364 | unsigned long max, unsigned int n, xa_mark_t);
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| 365 | void xa_destroy(struct xarray *);
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| 366 |
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| 367 | |
| 368 | * xa_init_flags() - Initialise an empty XArray with flags.
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| 369 | * @xa: XArray.
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| 370 | * @flags: XA_FLAG values.
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| 371 | *
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| 372 | * If you need to initialise an XArray with special flags (eg you need
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| 373 | * to take the lock from interrupt context), use this function instead
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| 374 | * of xa_init().
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| 375 | *
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| 376 | * Context: Any context.
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| 377 |
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| 378 | static inline void xa_init_flags(struct xarray *xa, gfp_t flags)
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| 379 | {
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| 380 | spin_lock_init(&xa->xa_lock);
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| 381 | xa->xa_flags = flags;
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| 382 | xa->xa_head = NULL;
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| 383 | }
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| 384 |
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| 385 | |
| 386 | * xa_init() - Initialise an empty XArray.
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| 387 | * @xa: XArray.
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| 388 | *
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| 389 | * An empty XArray is full of NULL entries.
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| 390 | *
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| 391 | * Context: Any context.
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| 392 |
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| 393 | static inline void xa_init(struct xarray *xa)
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| 394 | {
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| 395 | xa_init_flags(xa, 0);
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| 396 | }
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| 397 |
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| 398 | |
| 399 | * xa_empty() - Determine if an array has any present entries.
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| 400 | * @xa: XArray.
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| 401 | *
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| 402 | * Context: Any context.
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| 403 | * Return: %true if the array contains only NULL pointers.
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| 404 |
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| 405 | static inline bool xa_empty(const struct xarray *xa)
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| 406 | {
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| 407 | return xa->xa_head == NULL;
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| 408 | }
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| 409 |
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| 410 | |
| 411 | * xa_marked() - Inquire whether any entry in this array has a mark set
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| 412 | * @xa: Array
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| 413 | * @mark: Mark value
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| 414 | *
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| 415 | * Context: Any context.
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| 416 | * Return: %true if any entry has this mark set.
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| 417 |
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| 418 | static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark)
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| 419 | {
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| 420 | return xa->xa_flags & XA_FLAGS_MARK(mark);
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| 421 | }
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| 422 |
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| 423 | |
| 424 | * xa_for_each_range() - Iterate over a portion of an XArray.
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| 425 | * @xa: XArray.
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| 426 | * @index: Index of @entry.
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| 427 | * @entry: Entry retrieved from array.
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| 428 | * @start: First index to retrieve from array.
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| 429 | * @last: Last index to retrieve from array.
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| 430 | *
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| 431 | * During the iteration, @entry will have the value of the entry stored
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| 432 | * in @xa at @index. You may modify @index during the iteration if you
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| 433 | * want to skip or reprocess indices. It is safe to modify the array
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| 434 | * during the iteration. At the end of the iteration, @entry will be set
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| 435 | * to NULL and @index will have a value less than or equal to max.
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| 436 | *
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| 437 | * xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have
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| 438 | * to handle your own locking with xas_for_each(), and if you have to unlock
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| 439 | * after each iteration, it will also end up being O(n.log(n)).
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| 440 | * xa_for_each_range() will spin if it hits a retry entry; if you intend to
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| 441 | * see retry entries, you should use the xas_for_each() iterator instead.
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| 442 | * The xas_for_each() iterator will expand into more inline code than
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| 443 | * xa_for_each_range().
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| 444 | *
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| 445 | * Context: Any context. Takes and releases the RCU lock.
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| 446 |
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| 447 | #define xa_for_each_range(xa, index, entry, start, last) \
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| 448 | for (index = start, \
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| 449 | entry = xa_find(xa, &index, last, XA_PRESENT); \
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| 450 | entry; \
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| 451 | entry = xa_find_after(xa, &index, last, XA_PRESENT))
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| 452 |
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| 453 | |
| 454 | * xa_for_each_start() - Iterate over a portion of an XArray.
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| 455 | * @xa: XArray.
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| 456 | * @index: Index of @entry.
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| 457 | * @entry: Entry retrieved from array.
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| 458 | * @start: First index to retrieve from array.
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| 459 | *
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| 460 | * During the iteration, @entry will have the value of the entry stored
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| 461 | * in @xa at @index. You may modify @index during the iteration if you
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| 462 | * want to skip or reprocess indices. It is safe to modify the array
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| 463 | * during the iteration. At the end of the iteration, @entry will be set
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| 464 | * to NULL and @index will have a value less than or equal to max.
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| 465 | *
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| 466 | * xa_for_each_start() is O(n.log(n)) while xas_for_each() is O(n). You have
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| 467 | * to handle your own locking with xas_for_each(), and if you have to unlock
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| 468 | * after each iteration, it will also end up being O(n.log(n)).
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| 469 | * xa_for_each_start() will spin if it hits a retry entry; if you intend to
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| 470 | * see retry entries, you should use the xas_for_each() iterator instead.
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| 471 | * The xas_for_each() iterator will expand into more inline code than
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| 472 | * xa_for_each_start().
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| 473 | *
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| 474 | * Context: Any context. Takes and releases the RCU lock.
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| 475 |
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| 476 | #define xa_for_each_start(xa, index, entry, start) \
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| 477 | xa_for_each_range(xa, index, entry, start, ULONG_MAX)
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| 478 |
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| 479 | |
| 480 | * xa_for_each() - Iterate over present entries in an XArray.
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| 481 | * @xa: XArray.
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| 482 | * @index: Index of @entry.
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| 483 | * @entry: Entry retrieved from array.
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| 484 | *
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| 485 | * During the iteration, @entry will have the value of the entry stored
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| 486 | * in @xa at @index. You may modify @index during the iteration if you want
|
| 487 | * to skip or reprocess indices. It is safe to modify the array during the
|
| 488 | * iteration. At the end of the iteration, @entry will be set to NULL and
|
| 489 | * @index will have a value less than or equal to max.
|
| 490 | *
|
| 491 | * xa_for_each() is O(n.log(n)) while xas_for_each() is O(n). You have
|
| 492 | * to handle your own locking with xas_for_each(), and if you have to unlock
|
| 493 | * after each iteration, it will also end up being O(n.log(n)). xa_for_each()
|
| 494 | * will spin if it hits a retry entry; if you intend to see retry entries,
|
| 495 | * you should use the xas_for_each() iterator instead. The xas_for_each()
|
| 496 | * iterator will expand into more inline code than xa_for_each().
|
| 497 | *
|
| 498 | * Context: Any context. Takes and releases the RCU lock.
|
| 499 |
|
| 500 | #define xa_for_each(xa, index, entry) \
|
| 501 | xa_for_each_start(xa, index, entry, 0)
|
| 502 |
|
| 503 | |
| 504 | * xa_for_each_marked() - Iterate over marked entries in an XArray.
|
| 505 | * @xa: XArray.
|
| 506 | * @index: Index of @entry.
|
| 507 | * @entry: Entry retrieved from array.
|
| 508 | * @filter: Selection criterion.
|
| 509 | *
|
| 510 | * During the iteration, @entry will have the value of the entry stored
|
| 511 | * in @xa at @index. The iteration will skip all entries in the array
|
| 512 | * which do not match @filter. You may modify @index during the iteration
|
| 513 | * if you want to skip or reprocess indices. It is safe to modify the array
|
| 514 | * during the iteration. At the end of the iteration, @entry will be set to
|
| 515 | * NULL and @index will have a value less than or equal to max.
|
| 516 | *
|
| 517 | * xa_for_each_marked() is O(n.log(n)) while xas_for_each_marked() is O(n).
|
| 518 | * You have to handle your own locking with xas_for_each(), and if you have
|
| 519 | * to unlock after each iteration, it will also end up being O(n.log(n)).
|
| 520 | * xa_for_each_marked() will spin if it hits a retry entry; if you intend to
|
| 521 | * see retry entries, you should use the xas_for_each_marked() iterator
|
| 522 | * instead. The xas_for_each_marked() iterator will expand into more inline
|
| 523 | * code than xa_for_each_marked().
|
| 524 | *
|
| 525 | * Context: Any context. Takes and releases the RCU lock.
|
| 526 |
|
| 527 | #define xa_for_each_marked(xa, index, entry, filter) \
|
| 528 | for (index = 0, entry = xa_find(xa, &index, ULONG_MAX, filter); \
|
| 529 | entry; entry = xa_find_after(xa, &index, ULONG_MAX, filter))
|
| 530 |
|
| 531 | #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock)
|
| 532 | #define xa_lock(xa) spin_lock(&(xa)->xa_lock)
|
| 533 | #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock)
|
| 534 | #define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock)
|
| 535 | #define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock)
|
| 536 | #define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock)
|
| 537 | #define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock)
|
| 538 | #define xa_lock_irqsave(xa, flags) \
|
| 539 | spin_lock_irqsave(&(xa)->xa_lock, flags)
|
| 540 | #define xa_unlock_irqrestore(xa, flags) \
|
| 541 | spin_unlock_irqrestore(&(xa)->xa_lock, flags)
|
| 542 | #define xa_lock_nested(xa, subclass) \
|
| 543 | spin_lock_nested(&(xa)->xa_lock, subclass)
|
| 544 | #define xa_lock_bh_nested(xa, subclass) \
|
| 545 | spin_lock_bh_nested(&(xa)->xa_lock, subclass)
|
| 546 | #define xa_lock_irq_nested(xa, subclass) \
|
| 547 | spin_lock_irq_nested(&(xa)->xa_lock, subclass)
|
| 548 | #define xa_lock_irqsave_nested(xa, flags, subclass) \
|
| 549 | spin_lock_irqsave_nested(&(xa)->xa_lock, flags, subclass)
|
| 550 |
|
| 551 | |
| 552 | * Versions of the normal API which require the caller to hold the
|
| 553 | * xa_lock. If the GFP flags allow it, they will drop the lock to
|
| 554 | * allocate memory, then reacquire it afterwards. These functions
|
| 555 | * may also re-enable interrupts if the XArray flags indicate the
|
| 556 | * locking should be interrupt safe.
|
| 557 |
|
| 558 | void *__xa_erase(struct xarray *, unsigned long index);
|
| 559 | void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
|
| 560 | void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old,
|
| 561 | void *entry, gfp_t);
|
| 562 | int __must_check __xa_insert(struct xarray *, unsigned long index,
|
| 563 | void *entry, gfp_t);
|
| 564 | int __must_check __xa_alloc(struct xarray *, u32 *id, void *entry,
|
| 565 | struct xa_limit, gfp_t);
|
| 566 | int __must_check __xa_alloc_cyclic(struct xarray *, u32 *id, void *entry,
|
| 567 | struct xa_limit, u32 *next, gfp_t);
|
| 568 | void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t);
|
| 569 | void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t);
|
| 570 |
|
| 571 | |
| 572 | * xa_store_bh() - Store this entry in the XArray.
|
| 573 | * @xa: XArray.
|
| 574 | * @index: Index into array.
|
| 575 | * @entry: New entry.
|
| 576 | * @gfp: Memory allocation flags.
|
| 577 | *
|
| 578 | * This function is like calling xa_store() except it disables softirqs
|
| 579 | * while holding the array lock.
|
| 580 | *
|
| 581 | * Context: Any context. Takes and releases the xa_lock while
|
| 582 | * disabling softirqs.
|
| 583 | * Return: The old entry at this index or xa_err() if an error happened.
|
| 584 |
|
| 585 | static inline void *xa_store_bh(struct xarray *xa, unsigned long index,
|
| 586 | void *entry, gfp_t gfp)
|
| 587 | {
|
| 588 | void *curr;
|
| 589 |
|
| 590 | might_alloc(gfp);
|
| 591 | xa_lock_bh(xa);
|
| 592 | curr = __xa_store(xa, index, entry, gfp);
|
| 593 | xa_unlock_bh(xa);
|
| 594 |
|
| 595 | return curr;
|
| 596 | }
|
| 597 |
|
| 598 | |
| 599 | * xa_store_irq() - Store this entry in the XArray.
|
| 600 | * @xa: XArray.
|
| 601 | * @index: Index into array.
|
| 602 | * @entry: New entry.
|
| 603 | * @gfp: Memory allocation flags.
|
| 604 | *
|
| 605 | * This function is like calling xa_store() except it disables interrupts
|
| 606 | * while holding the array lock.
|
| 607 | *
|
| 608 | * Context: Process context. Takes and releases the xa_lock while
|
| 609 | * disabling interrupts.
|
| 610 | * Return: The old entry at this index or xa_err() if an error happened.
|
| 611 |
|
| 612 | static inline void *xa_store_irq(struct xarray *xa, unsigned long index,
|
| 613 | void *entry, gfp_t gfp)
|
| 614 | {
|
| 615 | void *curr;
|
| 616 |
|
| 617 | might_alloc(gfp);
|
| 618 | xa_lock_irq(xa);
|
| 619 | curr = __xa_store(xa, index, entry, gfp);
|
| 620 | xa_unlock_irq(xa);
|
| 621 |
|
| 622 | return curr;
|
| 623 | }
|
| 624 |
|
| 625 | |
| 626 | * xa_erase_bh() - Erase this entry from the XArray.
|
| 627 | * @xa: XArray.
|
| 628 | * @index: Index of entry.
|
| 629 | *
|
| 630 | * After this function returns, loading from @index will return %NULL.
|
| 631 | * If the index is part of a multi-index entry, all indices will be erased
|
| 632 | * and none of the entries will be part of a multi-index entry.
|
| 633 | *
|
| 634 | * Context: Any context. Takes and releases the xa_lock while
|
| 635 | * disabling softirqs.
|
| 636 | * Return: The entry which used to be at this index.
|
| 637 |
|
| 638 | static inline void *xa_erase_bh(struct xarray *xa, unsigned long index)
|
| 639 | {
|
| 640 | void *entry;
|
| 641 |
|
| 642 | xa_lock_bh(xa);
|
| 643 | entry = __xa_erase(xa, index);
|
| 644 | xa_unlock_bh(xa);
|
| 645 |
|
| 646 | return entry;
|
| 647 | }
|
| 648 |
|
| 649 | |
| 650 | * xa_erase_irq() - Erase this entry from the XArray.
|
| 651 | * @xa: XArray.
|
| 652 | * @index: Index of entry.
|
| 653 | *
|
| 654 | * After this function returns, loading from @index will return %NULL.
|
| 655 | * If the index is part of a multi-index entry, all indices will be erased
|
| 656 | * and none of the entries will be part of a multi-index entry.
|
| 657 | *
|
| 658 | * Context: Process context. Takes and releases the xa_lock while
|
| 659 | * disabling interrupts.
|
| 660 | * Return: The entry which used to be at this index.
|
| 661 |
|
| 662 | static inline void *xa_erase_irq(struct xarray *xa, unsigned long index)
|
| 663 | {
|
| 664 | void *entry;
|
| 665 |
|
| 666 | xa_lock_irq(xa);
|
| 667 | entry = __xa_erase(xa, index);
|
| 668 | xa_unlock_irq(xa);
|
| 669 |
|
| 670 | return entry;
|
| 671 | }
|
| 672 |
|
| 673 | |
| 674 | * xa_cmpxchg() - Conditionally replace an entry in the XArray.
|
| 675 | * @xa: XArray.
|
| 676 | * @index: Index into array.
|
| 677 | * @old: Old value to test against.
|
| 678 | * @entry: New value to place in array.
|
| 679 | * @gfp: Memory allocation flags.
|
| 680 | *
|
| 681 | * If the entry at @index is the same as @old, replace it with @entry.
|
| 682 | * If the return value is equal to @old, then the exchange was successful.
|
| 683 | *
|
| 684 | * Context: Any context. Takes and releases the xa_lock. May sleep
|
| 685 | * if the @gfp flags permit.
|
| 686 | * Return: The old value at this index or xa_err() if an error happened.
|
| 687 |
|
| 688 | static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index,
|
| 689 | void *old, void *entry, gfp_t gfp)
|
| 690 | {
|
| 691 | void *curr;
|
| 692 |
|
| 693 | might_alloc(gfp);
|
| 694 | xa_lock(xa);
|
| 695 | curr = __xa_cmpxchg(xa, index, old, entry, gfp);
|
| 696 | xa_unlock(xa);
|
| 697 |
|
| 698 | return curr;
|
| 699 | }
|
| 700 |
|
| 701 | |
| 702 | * xa_cmpxchg_bh() - Conditionally replace an entry in the XArray.
|
| 703 | * @xa: XArray.
|
| 704 | * @index: Index into array.
|
| 705 | * @old: Old value to test against.
|
| 706 | * @entry: New value to place in array.
|
| 707 | * @gfp: Memory allocation flags.
|
| 708 | *
|
| 709 | * This function is like calling xa_cmpxchg() except it disables softirqs
|
| 710 | * while holding the array lock.
|
| 711 | *
|
| 712 | * Context: Any context. Takes and releases the xa_lock while
|
| 713 | * disabling softirqs. May sleep if the @gfp flags permit.
|
| 714 | * Return: The old value at this index or xa_err() if an error happened.
|
| 715 |
|
| 716 | static inline void *xa_cmpxchg_bh(struct xarray *xa, unsigned long index,
|
| 717 | void *old, void *entry, gfp_t gfp)
|
| 718 | {
|
| 719 | void *curr;
|
| 720 |
|
| 721 | might_alloc(gfp);
|
| 722 | xa_lock_bh(xa);
|
| 723 | curr = __xa_cmpxchg(xa, index, old, entry, gfp);
|
| 724 | xa_unlock_bh(xa);
|
| 725 |
|
| 726 | return curr;
|
| 727 | }
|
| 728 |
|
| 729 | |
| 730 | * xa_cmpxchg_irq() - Conditionally replace an entry in the XArray.
|
| 731 | * @xa: XArray.
|
| 732 | * @index: Index into array.
|
| 733 | * @old: Old value to test against.
|
| 734 | * @entry: New value to place in array.
|
| 735 | * @gfp: Memory allocation flags.
|
| 736 | *
|
| 737 | * This function is like calling xa_cmpxchg() except it disables interrupts
|
| 738 | * while holding the array lock.
|
| 739 | *
|
| 740 | * Context: Process context. Takes and releases the xa_lock while
|
| 741 | * disabling interrupts. May sleep if the @gfp flags permit.
|
| 742 | * Return: The old value at this index or xa_err() if an error happened.
|
| 743 |
|
| 744 | static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index,
|
| 745 | void *old, void *entry, gfp_t gfp)
|
| 746 | {
|
| 747 | void *curr;
|
| 748 |
|
| 749 | might_alloc(gfp);
|
| 750 | xa_lock_irq(xa);
|
| 751 | curr = __xa_cmpxchg(xa, index, old, entry, gfp);
|
| 752 | xa_unlock_irq(xa);
|
| 753 |
|
| 754 | return curr;
|
| 755 | }
|
| 756 |
|
| 757 | |
| 758 | * xa_insert() - Store this entry in the XArray unless another entry is
|
| 759 | * already present.
|
| 760 | * @xa: XArray.
|
| 761 | * @index: Index into array.
|
| 762 | * @entry: New entry.
|
| 763 | * @gfp: Memory allocation flags.
|
| 764 | *
|
| 765 | * Inserting a NULL entry will store a reserved entry (like xa_reserve())
|
| 766 | * if no entry is present. Inserting will fail if a reserved entry is
|
| 767 | * present, even though loading from this index will return NULL.
|
| 768 | *
|
| 769 | * Context: Any context. Takes and releases the xa_lock. May sleep if
|
| 770 | * the @gfp flags permit.
|
| 771 | * Return: 0 if the store succeeded. -EBUSY if another entry was present.
|
| 772 | * -ENOMEM if memory could not be allocated.
|
| 773 |
|
| 774 | static inline int __must_check xa_insert(struct xarray *xa,
|
| 775 | unsigned long index, void *entry, gfp_t gfp)
|
| 776 | {
|
| 777 | int err;
|
| 778 |
|
| 779 | might_alloc(gfp);
|
| 780 | xa_lock(xa);
|
| 781 | err = __xa_insert(xa, index, entry, gfp);
|
| 782 | xa_unlock(xa);
|
| 783 |
|
| 784 | return err;
|
| 785 | }
|
| 786 |
|
| 787 | |
| 788 | * xa_insert_bh() - Store this entry in the XArray unless another entry is
|
| 789 | * already present.
|
| 790 | * @xa: XArray.
|
| 791 | * @index: Index into array.
|
| 792 | * @entry: New entry.
|
| 793 | * @gfp: Memory allocation flags.
|
| 794 | *
|
| 795 | * Inserting a NULL entry will store a reserved entry (like xa_reserve())
|
| 796 | * if no entry is present. Inserting will fail if a reserved entry is
|
| 797 | * present, even though loading from this index will return NULL.
|
| 798 | *
|
| 799 | * Context: Any context. Takes and releases the xa_lock while
|
| 800 | * disabling softirqs. May sleep if the @gfp flags permit.
|
| 801 | * Return: 0 if the store succeeded. -EBUSY if another entry was present.
|
| 802 | * -ENOMEM if memory could not be allocated.
|
| 803 |
|
| 804 | static inline int __must_check xa_insert_bh(struct xarray *xa,
|
| 805 | unsigned long index, void *entry, gfp_t gfp)
|
| 806 | {
|
| 807 | int err;
|
| 808 |
|
| 809 | might_alloc(gfp);
|
| 810 | xa_lock_bh(xa);
|
| 811 | err = __xa_insert(xa, index, entry, gfp);
|
| 812 | xa_unlock_bh(xa);
|
| 813 |
|
| 814 | return err;
|
| 815 | }
|
| 816 |
|
| 817 | |
| 818 | * xa_insert_irq() - Store this entry in the XArray unless another entry is
|
| 819 | * already present.
|
| 820 | * @xa: XArray.
|
| 821 | * @index: Index into array.
|
| 822 | * @entry: New entry.
|
| 823 | * @gfp: Memory allocation flags.
|
| 824 | *
|
| 825 | * Inserting a NULL entry will store a reserved entry (like xa_reserve())
|
| 826 | * if no entry is present. Inserting will fail if a reserved entry is
|
| 827 | * present, even though loading from this index will return NULL.
|
| 828 | *
|
| 829 | * Context: Process context. Takes and releases the xa_lock while
|
| 830 | * disabling interrupts. May sleep if the @gfp flags permit.
|
| 831 | * Return: 0 if the store succeeded. -EBUSY if another entry was present.
|
| 832 | * -ENOMEM if memory could not be allocated.
|
| 833 |
|
| 834 | static inline int __must_check xa_insert_irq(struct xarray *xa,
|
| 835 | unsigned long index, void *entry, gfp_t gfp)
|
| 836 | {
|
| 837 | int err;
|
| 838 |
|
| 839 | might_alloc(gfp);
|
| 840 | xa_lock_irq(xa);
|
| 841 | err = __xa_insert(xa, index, entry, gfp);
|
| 842 | xa_unlock_irq(xa);
|
| 843 |
|
| 844 | return err;
|
| 845 | }
|
| 846 |
|
| 847 | |
| 848 | * xa_alloc() - Find somewhere to store this entry in the XArray.
|
| 849 | * @xa: XArray.
|
| 850 | * @id: Pointer to ID.
|
| 851 | * @entry: New entry.
|
| 852 | * @limit: Range of ID to allocate.
|
| 853 | * @gfp: Memory allocation flags.
|
| 854 | *
|
| 855 | * Finds an empty entry in @xa between @limit.min and @limit.max,
|
| 856 | * stores the index into the @id pointer, then stores the entry at
|
| 857 | * that index. A concurrent lookup will not see an uninitialised @id.
|
| 858 | *
|
| 859 | * Context: Any context. Takes and releases the xa_lock. May sleep if
|
| 860 | * the @gfp flags permit.
|
| 861 | * Return: 0 on success, -ENOMEM if memory could not be allocated or
|
| 862 | * -EBUSY if there are no free entries in @limit.
|
| 863 |
|
| 864 | static inline __must_check int xa_alloc(struct xarray *xa, u32 *id,
|
| 865 | void *entry, struct xa_limit limit, gfp_t gfp)
|
| 866 | {
|
| 867 | int err;
|
| 868 |
|
| 869 | might_alloc(gfp);
|
| 870 | xa_lock(xa);
|
| 871 | err = __xa_alloc(xa, id, entry, limit, gfp);
|
| 872 | xa_unlock(xa);
|
| 873 |
|
| 874 | return err;
|
| 875 | }
|
| 876 |
|
| 877 | |
| 878 | * xa_alloc_bh() - Find somewhere to store this entry in the XArray.
|
| 879 | * @xa: XArray.
|
| 880 | * @id: Pointer to ID.
|
| 881 | * @entry: New entry.
|
| 882 | * @limit: Range of ID to allocate.
|
| 883 | * @gfp: Memory allocation flags.
|
| 884 | *
|
| 885 | * Finds an empty entry in @xa between @limit.min and @limit.max,
|
| 886 | * stores the index into the @id pointer, then stores the entry at
|
| 887 | * that index. A concurrent lookup will not see an uninitialised @id.
|
| 888 | *
|
| 889 | * Context: Any context. Takes and releases the xa_lock while
|
| 890 | * disabling softirqs. May sleep if the @gfp flags permit.
|
| 891 | * Return: 0 on success, -ENOMEM if memory could not be allocated or
|
| 892 | * -EBUSY if there are no free entries in @limit.
|
| 893 |
|
| 894 | static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id,
|
| 895 | void *entry, struct xa_limit limit, gfp_t gfp)
|
| 896 | {
|
| 897 | int err;
|
| 898 |
|
| 899 | might_alloc(gfp);
|
| 900 | xa_lock_bh(xa);
|
| 901 | err = __xa_alloc(xa, id, entry, limit, gfp);
|
| 902 | xa_unlock_bh(xa);
|
| 903 |
|
| 904 | return err;
|
| 905 | }
|
| 906 |
|
| 907 | |
| 908 | * xa_alloc_irq() - Find somewhere to store this entry in the XArray.
|
| 909 | * @xa: XArray.
|
| 910 | * @id: Pointer to ID.
|
| 911 | * @entry: New entry.
|
| 912 | * @limit: Range of ID to allocate.
|
| 913 | * @gfp: Memory allocation flags.
|
| 914 | *
|
| 915 | * Finds an empty entry in @xa between @limit.min and @limit.max,
|
| 916 | * stores the index into the @id pointer, then stores the entry at
|
| 917 | * that index. A concurrent lookup will not see an uninitialised @id.
|
| 918 | *
|
| 919 | * Context: Process context. Takes and releases the xa_lock while
|
| 920 | * disabling interrupts. May sleep if the @gfp flags permit.
|
| 921 | * Return: 0 on success, -ENOMEM if memory could not be allocated or
|
| 922 | * -EBUSY if there are no free entries in @limit.
|
| 923 |
|
| 924 | static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id,
|
| 925 | void *entry, struct xa_limit limit, gfp_t gfp)
|
| 926 | {
|
| 927 | int err;
|
| 928 |
|
| 929 | might_alloc(gfp);
|
| 930 | xa_lock_irq(xa);
|
| 931 | err = __xa_alloc(xa, id, entry, limit, gfp);
|
| 932 | xa_unlock_irq(xa);
|
| 933 |
|
| 934 | return err;
|
| 935 | }
|
| 936 |
|
| 937 | |
| 938 | * xa_alloc_cyclic() - Find somewhere to store this entry in the XArray.
|
| 939 | * @xa: XArray.
|
| 940 | * @id: Pointer to ID.
|
| 941 | * @entry: New entry.
|
| 942 | * @limit: Range of allocated ID.
|
| 943 | * @next: Pointer to next ID to allocate.
|
| 944 | * @gfp: Memory allocation flags.
|
| 945 | *
|
| 946 | * Finds an empty entry in @xa between @limit.min and @limit.max,
|
| 947 | * stores the index into the @id pointer, then stores the entry at
|
| 948 | * that index. A concurrent lookup will not see an uninitialised @id.
|
| 949 | * The search for an empty entry will start at @next and will wrap
|
| 950 | * around if necessary.
|
| 951 | *
|
| 952 | * Context: Any context. Takes and releases the xa_lock. May sleep if
|
| 953 | * the @gfp flags permit.
|
| 954 | * Return: 0 if the allocation succeeded without wrapping. 1 if the
|
| 955 | * allocation succeeded after wrapping, -ENOMEM if memory could not be
|
| 956 | * allocated or -EBUSY if there are no free entries in @limit.
|
| 957 |
|
| 958 | static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry,
|
| 959 | struct xa_limit limit, u32 *next, gfp_t gfp)
|
| 960 | {
|
| 961 | int err;
|
| 962 |
|
| 963 | might_alloc(gfp);
|
| 964 | xa_lock(xa);
|
| 965 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp);
|
| 966 | xa_unlock(xa);
|
| 967 |
|
| 968 | return err;
|
| 969 | }
|
| 970 |
|
| 971 | |
| 972 | * xa_alloc_cyclic_bh() - Find somewhere to store this entry in the XArray.
|
| 973 | * @xa: XArray.
|
| 974 | * @id: Pointer to ID.
|
| 975 | * @entry: New entry.
|
| 976 | * @limit: Range of allocated ID.
|
| 977 | * @next: Pointer to next ID to allocate.
|
| 978 | * @gfp: Memory allocation flags.
|
| 979 | *
|
| 980 | * Finds an empty entry in @xa between @limit.min and @limit.max,
|
| 981 | * stores the index into the @id pointer, then stores the entry at
|
| 982 | * that index. A concurrent lookup will not see an uninitialised @id.
|
| 983 | * The search for an empty entry will start at @next and will wrap
|
| 984 | * around if necessary.
|
| 985 | *
|
| 986 | * Context: Any context. Takes and releases the xa_lock while
|
| 987 | * disabling softirqs. May sleep if the @gfp flags permit.
|
| 988 | * Return: 0 if the allocation succeeded without wrapping. 1 if the
|
| 989 | * allocation succeeded after wrapping, -ENOMEM if memory could not be
|
| 990 | * allocated or -EBUSY if there are no free entries in @limit.
|
| 991 |
|
| 992 | static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry,
|
| 993 | struct xa_limit limit, u32 *next, gfp_t gfp)
|
| 994 | {
|
| 995 | int err;
|
| 996 |
|
| 997 | might_alloc(gfp);
|
| 998 | xa_lock_bh(xa);
|
| 999 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp);
|
| 1000 | xa_unlock_bh(xa);
|
| 1001 |
|
| 1002 | return err;
|
| 1003 | }
|
| 1004 |
|
| 1005 | |
| 1006 | * xa_alloc_cyclic_irq() - Find somewhere to store this entry in the XArray.
|
| 1007 | * @xa: XArray.
|
| 1008 | * @id: Pointer to ID.
|
| 1009 | * @entry: New entry.
|
| 1010 | * @limit: Range of allocated ID.
|
| 1011 | * @next: Pointer to next ID to allocate.
|
| 1012 | * @gfp: Memory allocation flags.
|
| 1013 | *
|
| 1014 | * Finds an empty entry in @xa between @limit.min and @limit.max,
|
| 1015 | * stores the index into the @id pointer, then stores the entry at
|
| 1016 | * that index. A concurrent lookup will not see an uninitialised @id.
|
| 1017 | * The search for an empty entry will start at @next and will wrap
|
| 1018 | * around if necessary.
|
| 1019 | *
|
| 1020 | * Context: Process context. Takes and releases the xa_lock while
|
| 1021 | * disabling interrupts. May sleep if the @gfp flags permit.
|
| 1022 | * Return: 0 if the allocation succeeded without wrapping. 1 if the
|
| 1023 | * allocation succeeded after wrapping, -ENOMEM if memory could not be
|
| 1024 | * allocated or -EBUSY if there are no free entries in @limit.
|
| 1025 |
|
| 1026 | static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, void *entry,
|
| 1027 | struct xa_limit limit, u32 *next, gfp_t gfp)
|
| 1028 | {
|
| 1029 | int err;
|
| 1030 |
|
| 1031 | might_alloc(gfp);
|
| 1032 | xa_lock_irq(xa);
|
| 1033 | err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp);
|
| 1034 | xa_unlock_irq(xa);
|
| 1035 |
|
| 1036 | return err;
|
| 1037 | }
|
| 1038 |
|
| 1039 | |
| 1040 | * xa_reserve() - Reserve this index in the XArray.
|
| 1041 | * @xa: XArray.
|
| 1042 | * @index: Index into array.
|
| 1043 | * @gfp: Memory allocation flags.
|
| 1044 | *
|
| 1045 | * Ensures there is somewhere to store an entry at @index in the array.
|
| 1046 | * If there is already something stored at @index, this function does
|
| 1047 | * nothing. If there was nothing there, the entry is marked as reserved.
|
| 1048 | * Loading from a reserved entry returns a %NULL pointer.
|
| 1049 | *
|
| 1050 | * If you do not use the entry that you have reserved, call xa_release()
|
| 1051 | * or xa_erase() to free any unnecessary memory.
|
| 1052 | *
|
| 1053 | * Context: Any context. Takes and releases the xa_lock.
|
| 1054 | * May sleep if the @gfp flags permit.
|
| 1055 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed.
|
| 1056 |
|
| 1057 | static inline __must_check
|
| 1058 | int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
|
| 1059 | {
|
| 1060 | return xa_err(xa_cmpxchg(xa, index, NULL, XA_ZERO_ENTRY, gfp));
|
| 1061 | }
|
| 1062 |
|
| 1063 | |
| 1064 | * xa_reserve_bh() - Reserve this index in the XArray.
|
| 1065 | * @xa: XArray.
|
| 1066 | * @index: Index into array.
|
| 1067 | * @gfp: Memory allocation flags.
|
| 1068 | *
|
| 1069 | * A softirq-disabling version of xa_reserve().
|
| 1070 | *
|
| 1071 | * Context: Any context. Takes and releases the xa_lock while
|
| 1072 | * disabling softirqs.
|
| 1073 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed.
|
| 1074 |
|
| 1075 | static inline __must_check
|
| 1076 | int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp)
|
| 1077 | {
|
| 1078 | return xa_err(xa_cmpxchg_bh(xa, index, NULL, XA_ZERO_ENTRY, gfp));
|
| 1079 | }
|
| 1080 |
|
| 1081 | |
| 1082 | * xa_reserve_irq() - Reserve this index in the XArray.
|
| 1083 | * @xa: XArray.
|
| 1084 | * @index: Index into array.
|
| 1085 | * @gfp: Memory allocation flags.
|
| 1086 | *
|
| 1087 | * An interrupt-disabling version of xa_reserve().
|
| 1088 | *
|
| 1089 | * Context: Process context. Takes and releases the xa_lock while
|
| 1090 | * disabling interrupts.
|
| 1091 | * Return: 0 if the reservation succeeded or -ENOMEM if it failed.
|
| 1092 |
|
| 1093 | static inline __must_check
|
| 1094 | int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp)
|
| 1095 | {
|
| 1096 | return xa_err(xa_cmpxchg_irq(xa, index, NULL, XA_ZERO_ENTRY, gfp));
|
| 1097 | }
|
| 1098 |
|
| 1099 | |
| 1100 | * xa_release() - Release a reserved entry.
|
| 1101 | * @xa: XArray.
|
| 1102 | * @index: Index of entry.
|
| 1103 | *
|
| 1104 | * After calling xa_reserve(), you can call this function to release the
|
| 1105 | * reservation. If the entry at @index has been stored to, this function
|
| 1106 | * will do nothing.
|
| 1107 |
|
| 1108 | static inline void xa_release(struct xarray *xa, unsigned long index)
|
| 1109 | {
|
| 1110 | xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, 0);
|
| 1111 | }
|
| 1112 |
|
| 1113 |
|
| 1114 |
|
| 1115 | |
| 1116 | * The xarray is constructed out of a set of 'chunks' of pointers. Choosing
|
| 1117 | * the best chunk size requires some tradeoffs. A power of two recommends
|
| 1118 | * itself so that we can walk the tree based purely on shifts and masks.
|
| 1119 | * Generally, the larger the better; as the number of slots per level of the
|
| 1120 | * tree increases, the less tall the tree needs to be. But that needs to be
|
| 1121 | * balanced against the memory consumption of each node. On a 64-bit system,
|
| 1122 | * xa_node is currently 576 bytes, and we get 7 of them per 4kB page. If we
|
| 1123 | * doubled the number of slots per node, we'd get only 3 nodes per 4kB page.
|
| 1124 |
|
| 1125 | #ifndef XA_CHUNK_SHIFT
|
| 1126 | #define XA_CHUNK_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)
|
| 1127 | #endif
|
| 1128 | #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT)
|
| 1129 | #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1)
|
| 1130 | #define XA_MAX_MARKS 3
|
| 1131 | #define XA_MARK_LONGS DIV_ROUND_UP(XA_CHUNK_SIZE, BITS_PER_LONG)
|
| 1132 |
|
| 1133 | |
| 1134 | * @count is the count of every non-NULL element in the ->slots array
|
| 1135 | * whether that is a value entry, a retry entry, a user pointer,
|
| 1136 | * a sibling entry or a pointer to the next level of the tree.
|
| 1137 | * @nr_values is the count of every element in ->slots which is
|
| 1138 | * either a value entry or a sibling of a value entry.
|
| 1139 |
|
| 1140 | struct xa_node {
|
| 1141 | unsigned char shift;
|
| 1142 | unsigned char offset;
|
| 1143 | unsigned char count;
|
| 1144 | unsigned char nr_values;
|
| 1145 | struct xa_node __rcu *parent;
|
| 1146 | struct xarray *array;
|
| 1147 | union {
|
| 1148 | struct list_head private_list;
|
| 1149 | struct rcu_head rcu_head;
|
| 1150 | };
|
| 1151 | void __rcu *slots[XA_CHUNK_SIZE];
|
| 1152 | union {
|
| 1153 | unsigned long tags[XA_MAX_MARKS][XA_MARK_LONGS];
|
| 1154 | unsigned long marks[XA_MAX_MARKS][XA_MARK_LONGS];
|
| 1155 | };
|
| 1156 | };
|
| 1157 |
|
| 1158 | void xa_dump(const struct xarray *);
|
| 1159 | void xa_dump_node(const struct xa_node *);
|
| 1160 |
|
| 1161 | #ifdef XA_DEBUG
|
| 1162 | #define XA_BUG_ON(xa, x) do { \
|
| 1163 | if (x) { \
|
| 1164 | xa_dump(xa); \
|
| 1165 | BUG(); \
|
| 1166 | } \
|
| 1167 | } while (0)
|
| 1168 | #define XA_NODE_BUG_ON(node, x) do { \
|
| 1169 | if (x) { \
|
| 1170 | if (node) xa_dump_node(node); \
|
| 1171 | BUG(); \
|
| 1172 | } \
|
| 1173 | } while (0)
|
| 1174 | #else
|
| 1175 | #define XA_BUG_ON(xa, x) do { } while (0)
|
| 1176 | #define XA_NODE_BUG_ON(node, x) do { } while (0)
|
| 1177 | #endif
|
| 1178 |
|
| 1179 |
|
| 1180 | static inline void *xa_head(const struct xarray *xa)
|
| 1181 | {
|
| 1182 | return rcu_dereference_check(xa->xa_head,
|
| 1183 | lockdep_is_held(&xa->xa_lock));
|
| 1184 | }
|
| 1185 |
|
| 1186 |
|
| 1187 | static inline void *xa_head_locked(const struct xarray *xa)
|
| 1188 | {
|
| 1189 | return rcu_dereference_protected(xa->xa_head,
|
| 1190 | lockdep_is_held(&xa->xa_lock));
|
| 1191 | }
|
| 1192 |
|
| 1193 |
|
| 1194 | static inline void *xa_entry(const struct xarray *xa,
|
| 1195 | const struct xa_node *node, unsigned int offset)
|
| 1196 | {
|
| 1197 | XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE);
|
| 1198 | return rcu_dereference_check(node->slots[offset],
|
| 1199 | lockdep_is_held(&xa->xa_lock));
|
| 1200 | }
|
| 1201 |
|
| 1202 |
|
| 1203 | static inline void *xa_entry_locked(const struct xarray *xa,
|
| 1204 | const struct xa_node *node, unsigned int offset)
|
| 1205 | {
|
| 1206 | XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE);
|
| 1207 | return rcu_dereference_protected(node->slots[offset],
|
| 1208 | lockdep_is_held(&xa->xa_lock));
|
| 1209 | }
|
| 1210 |
|
| 1211 |
|
| 1212 | static inline struct xa_node *xa_parent(const struct xarray *xa,
|
| 1213 | const struct xa_node *node)
|
| 1214 | {
|
| 1215 | return rcu_dereference_check(node->parent,
|
| 1216 | lockdep_is_held(&xa->xa_lock));
|
| 1217 | }
|
| 1218 |
|
| 1219 |
|
| 1220 | static inline struct xa_node *xa_parent_locked(const struct xarray *xa,
|
| 1221 | const struct xa_node *node)
|
| 1222 | {
|
| 1223 | return rcu_dereference_protected(node->parent,
|
| 1224 | lockdep_is_held(&xa->xa_lock));
|
| 1225 | }
|
| 1226 |
|
| 1227 |
|
| 1228 | static inline void *xa_mk_node(const struct xa_node *node)
|
| 1229 | {
|
| 1230 | return (void *)((unsigned long)node | 2);
|
| 1231 | }
|
| 1232 |
|
| 1233 |
|
| 1234 | static inline struct xa_node *xa_to_node(const void *entry)
|
| 1235 | {
|
| 1236 | return (struct xa_node *)((unsigned long)entry - 2);
|
| 1237 | }
|
| 1238 |
|
| 1239 |
|
| 1240 | static inline bool xa_is_node(const void *entry)
|
| 1241 | {
|
| 1242 | return xa_is_internal(entry) && (unsigned long)entry > 4096;
|
| 1243 | }
|
| 1244 |
|
| 1245 |
|
| 1246 | static inline void *xa_mk_sibling(unsigned int offset)
|
| 1247 | {
|
| 1248 | return xa_mk_internal(offset);
|
| 1249 | }
|
| 1250 |
|
| 1251 |
|
| 1252 | static inline unsigned long xa_to_sibling(const void *entry)
|
| 1253 | {
|
| 1254 | return xa_to_internal(entry);
|
| 1255 | }
|
| 1256 |
|
| 1257 | |
| 1258 | * xa_is_sibling() - Is the entry a sibling entry?
|
| 1259 | * @entry: Entry retrieved from the XArray
|
| 1260 | *
|
| 1261 | * Return: %true if the entry is a sibling entry.
|
| 1262 |
|
| 1263 | static inline bool xa_is_sibling(const void *entry)
|
| 1264 | {
|
| 1265 | return IS_ENABLED(CONFIG_XARRAY_MULTI) && xa_is_internal(entry) &&
|
| 1266 | (entry < xa_mk_sibling(XA_CHUNK_SIZE - 1));
|
| 1267 | }
|
| 1268 |
|
| 1269 | #define XA_RETRY_ENTRY xa_mk_internal(256)
|
| 1270 |
|
| 1271 | |
| 1272 | * xa_is_retry() - Is the entry a retry entry?
|
| 1273 | * @entry: Entry retrieved from the XArray
|
| 1274 | *
|
| 1275 | * Return: %true if the entry is a retry entry.
|
| 1276 |
|
| 1277 | static inline bool xa_is_retry(const void *entry)
|
| 1278 | {
|
| 1279 | return unlikely(entry == XA_RETRY_ENTRY);
|
| 1280 | }
|
| 1281 |
|
| 1282 | |
| 1283 | * xa_is_advanced() - Is the entry only permitted for the advanced API?
|
| 1284 | * @entry: Entry to be stored in the XArray.
|
| 1285 | *
|
| 1286 | * Return: %true if the entry cannot be stored by the normal API.
|
| 1287 |
|
| 1288 | static inline bool xa_is_advanced(const void *entry)
|
| 1289 | {
|
| 1290 | return xa_is_internal(entry) && (entry <= XA_RETRY_ENTRY);
|
| 1291 | }
|
| 1292 |
|
| 1293 | |
| 1294 | * typedef xa_update_node_t - A callback function from the XArray.
|
| 1295 | * @node: The node which is being processed
|
| 1296 | *
|
| 1297 | * This function is called every time the XArray updates the count of
|
| 1298 | * present and value entries in a node. It allows advanced users to
|
| 1299 | * maintain the private_list in the node.
|
| 1300 | *
|
| 1301 | * Context: The xa_lock is held and interrupts may be disabled.
|
| 1302 | * Implementations should not drop the xa_lock, nor re-enable
|
| 1303 | * interrupts.
|
| 1304 |
|
| 1305 | typedef void (*xa_update_node_t)(struct xa_node *node);
|
| 1306 |
|
| 1307 | void xa_delete_node(struct xa_node *, xa_update_node_t);
|
| 1308 |
|
| 1309 | |
| 1310 | * The xa_state is opaque to its users. It contains various different pieces
|
| 1311 | * of state involved in the current operation on the XArray. It should be
|
| 1312 | * declared on the stack and passed between the various internal routines.
|
| 1313 | * The various elements in it should not be accessed directly, but only
|
| 1314 | * through the provided accessor functions. The below documentation is for
|
| 1315 | * the benefit of those working on the code, not for users of the XArray.
|
| 1316 | *
|
| 1317 | * @xa_node usually points to the xa_node containing the slot we're operating
|
| 1318 | * on (and @xa_offset is the offset in the slots array). If there is a
|
| 1319 | * single entry in the array at index 0, there are no allocated xa_nodes to
|
| 1320 | * point to, and so we store %NULL in @xa_node. @xa_node is set to
|
| 1321 | * the value %XAS_RESTART if the xa_state is not walked to the correct
|
| 1322 | * position in the tree of nodes for this operation. If an error occurs
|
| 1323 | * during an operation, it is set to an %XAS_ERROR value. If we run off the
|
| 1324 | * end of the allocated nodes, it is set to %XAS_BOUNDS.
|
| 1325 |
|
| 1326 | struct xa_state {
|
| 1327 | struct xarray *xa;
|
| 1328 | unsigned long xa_index;
|
| 1329 | unsigned char xa_shift;
|
| 1330 | unsigned char xa_sibs;
|
| 1331 | unsigned char xa_offset;
|
| 1332 | unsigned char xa_pad;
|
| 1333 | struct xa_node *xa_node;
|
| 1334 | struct xa_node *xa_alloc;
|
| 1335 | xa_update_node_t xa_update;
|
| 1336 | struct list_lru *xa_lru;
|
| 1337 | };
|
| 1338 |
|
| 1339 | |
| 1340 | * We encode errnos in the xas->xa_node. If an error has happened, we need to
|
| 1341 | * drop the lock to fix it, and once we've done so the xa_state is invalid.
|
| 1342 |
|
| 1343 | #define XA_ERROR(errno) ((struct xa_node *)(((unsigned long)errno << 2) | 2UL))
|
| 1344 | #define XAS_BOUNDS ((struct xa_node *)1UL)
|
| 1345 | #define XAS_RESTART ((struct xa_node *)3UL)
|
| 1346 |
|
| 1347 | #define __XA_STATE(array, index, shift, sibs) { \
|
| 1348 | .xa = array, \
|
| 1349 | .xa_index = index, \
|
| 1350 | .xa_shift = shift, \
|
| 1351 | .xa_sibs = sibs, \
|
| 1352 | .xa_offset = 0, \
|
| 1353 | .xa_pad = 0, \
|
| 1354 | .xa_node = XAS_RESTART, \
|
| 1355 | .xa_alloc = NULL, \
|
| 1356 | .xa_update = NULL, \
|
| 1357 | .xa_lru = NULL, \
|
| 1358 | }
|
| 1359 |
|
| 1360 | |
| 1361 | * XA_STATE() - Declare an XArray operation state.
|
| 1362 | * @name: Name of this operation state (usually xas).
|
| 1363 | * @array: Array to operate on.
|
| 1364 | * @index: Initial index of interest.
|
| 1365 | *
|
| 1366 | * Declare and initialise an xa_state on the stack.
|
| 1367 |
|
| 1368 | #define XA_STATE(name, array, index) \
|
| 1369 | struct xa_state name = __XA_STATE(array, index, 0, 0)
|
| 1370 |
|
| 1371 | |
| 1372 | * XA_STATE_ORDER() - Declare an XArray operation state.
|
| 1373 | * @name: Name of this operation state (usually xas).
|
| 1374 | * @array: Array to operate on.
|
| 1375 | * @index: Initial index of interest.
|
| 1376 | * @order: Order of entry.
|
| 1377 | *
|
| 1378 | * Declare and initialise an xa_state on the stack. This variant of
|
| 1379 | * XA_STATE() allows you to specify the 'order' of the element you
|
| 1380 | * want to operate on.`
|
| 1381 |
|
| 1382 | #define XA_STATE_ORDER(name, array, index, order) \
|
| 1383 | struct xa_state name = __XA_STATE(array, \
|
| 1384 | (index >> order) << order, \
|
| 1385 | order - (order % XA_CHUNK_SHIFT), \
|
| 1386 | (1U << (order % XA_CHUNK_SHIFT)) - 1)
|
| 1387 |
|
| 1388 | #define xas_marked(xas, mark) xa_marked((xas)->xa, (mark))
|
| 1389 | #define xas_trylock(xas) xa_trylock((xas)->xa)
|
| 1390 | #define xas_lock(xas) xa_lock((xas)->xa)
|
| 1391 | #define xas_unlock(xas) xa_unlock((xas)->xa)
|
| 1392 | #define xas_lock_bh(xas) xa_lock_bh((xas)->xa)
|
| 1393 | #define xas_unlock_bh(xas) xa_unlock_bh((xas)->xa)
|
| 1394 | #define xas_lock_irq(xas) xa_lock_irq((xas)->xa)
|
| 1395 | #define xas_unlock_irq(xas) xa_unlock_irq((xas)->xa)
|
| 1396 | #define xas_lock_irqsave(xas, flags) \
|
| 1397 | xa_lock_irqsave((xas)->xa, flags)
|
| 1398 | #define xas_unlock_irqrestore(xas, flags) \
|
| 1399 | xa_unlock_irqrestore((xas)->xa, flags)
|
| 1400 |
|
| 1401 | |
| 1402 | * xas_error() - Return an errno stored in the xa_state.
|
| 1403 | * @xas: XArray operation state.
|
| 1404 | *
|
| 1405 | * Return: 0 if no error has been noted. A negative errno if one has.
|
| 1406 |
|
| 1407 | static inline int xas_error(const struct xa_state *xas)
|
| 1408 | {
|
| 1409 | return xa_err(xas->xa_node);
|
| 1410 | }
|
| 1411 |
|
| 1412 | |
| 1413 | * xas_set_err() - Note an error in the xa_state.
|
| 1414 | * @xas: XArray operation state.
|
| 1415 | * @err: Negative error number.
|
| 1416 | *
|
| 1417 | * Only call this function with a negative @err; zero or positive errors
|
| 1418 | * will probably not behave the way you think they should. If you want
|
| 1419 | * to clear the error from an xa_state, use xas_reset().
|
| 1420 |
|
| 1421 | static inline void xas_set_err(struct xa_state *xas, long err)
|
| 1422 | {
|
| 1423 | xas->xa_node = XA_ERROR(err);
|
| 1424 | }
|
| 1425 |
|
| 1426 | |
| 1427 | * xas_invalid() - Is the xas in a retry or error state?
|
| 1428 | * @xas: XArray operation state.
|
| 1429 | *
|
| 1430 | * Return: %true if the xas cannot be used for operations.
|
| 1431 |
|
| 1432 | static inline bool xas_invalid(const struct xa_state *xas)
|
| 1433 | {
|
| 1434 | return (unsigned long)xas->xa_node & 3;
|
| 1435 | }
|
| 1436 |
|
| 1437 | |
| 1438 | * xas_valid() - Is the xas a valid cursor into the array?
|
| 1439 | * @xas: XArray operation state.
|
| 1440 | *
|
| 1441 | * Return: %true if the xas can be used for operations.
|
| 1442 |
|
| 1443 | static inline bool xas_valid(const struct xa_state *xas)
|
| 1444 | {
|
| 1445 | return !xas_invalid(xas);
|
| 1446 | }
|
| 1447 |
|
| 1448 | |
| 1449 | * xas_is_node() - Does the xas point to a node?
|
| 1450 | * @xas: XArray operation state.
|
| 1451 | *
|
| 1452 | * Return: %true if the xas currently references a node.
|
| 1453 |
|
| 1454 | static inline bool xas_is_node(const struct xa_state *xas)
|
| 1455 | {
|
| 1456 | return xas_valid(xas) && xas->xa_node;
|
| 1457 | }
|
| 1458 |
|
| 1459 |
|
| 1460 | static inline bool xas_not_node(struct xa_node *node)
|
| 1461 | {
|
| 1462 | return ((unsigned long)node & 3) || !node;
|
| 1463 | }
|
| 1464 |
|
| 1465 |
|
| 1466 | static inline bool xas_frozen(struct xa_node *node)
|
| 1467 | {
|
| 1468 | return (unsigned long)node & 2;
|
| 1469 | }
|
| 1470 |
|
| 1471 |
|
| 1472 | static inline bool xas_top(struct xa_node *node)
|
| 1473 | {
|
| 1474 | return node <= XAS_RESTART;
|
| 1475 | }
|
| 1476 |
|
| 1477 | |
| 1478 | * xas_reset() - Reset an XArray operation state.
|
| 1479 | * @xas: XArray operation state.
|
| 1480 | *
|
| 1481 | * Resets the error or walk state of the @xas so future walks of the
|
| 1482 | * array will start from the root. Use this if you have dropped the
|
| 1483 | * xarray lock and want to reuse the xa_state.
|
| 1484 | *
|
| 1485 | * Context: Any context.
|
| 1486 |
|
| 1487 | static inline void xas_reset(struct xa_state *xas)
|
| 1488 | {
|
| 1489 | xas->xa_node = XAS_RESTART;
|
| 1490 | }
|
| 1491 |
|
| 1492 | |
| 1493 | * xas_retry() - Retry the operation if appropriate.
|
| 1494 | * @xas: XArray operation state.
|
| 1495 | * @entry: Entry from xarray.
|
| 1496 | *
|
| 1497 | * The advanced functions may sometimes return an internal entry, such as
|
| 1498 | * a retry entry or a zero entry. This function sets up the @xas to restart
|
| 1499 | * the walk from the head of the array if needed.
|
| 1500 | *
|
| 1501 | * Context: Any context.
|
| 1502 | * Return: true if the operation needs to be retried.
|
| 1503 |
|
| 1504 | static inline bool xas_retry(struct xa_state *xas, const void *entry)
|
| 1505 | {
|
| 1506 | if (xa_is_zero(entry))
|
| 1507 | return true;
|
| 1508 | if (!xa_is_retry(entry))
|
| 1509 | return false;
|
| 1510 | xas_reset(xas);
|
| 1511 | return true;
|
| 1512 | }
|
| 1513 |
|
| 1514 | void *xas_load(struct xa_state *);
|
| 1515 | void *xas_store(struct xa_state *, void *entry);
|
| 1516 | void *xas_find(struct xa_state *, unsigned long max);
|
| 1517 | void *xas_find_conflict(struct xa_state *);
|
| 1518 |
|
| 1519 | bool xas_get_mark(const struct xa_state *, xa_mark_t);
|
| 1520 | void xas_set_mark(const struct xa_state *, xa_mark_t);
|
| 1521 | void xas_clear_mark(const struct xa_state *, xa_mark_t);
|
| 1522 | void *xas_find_marked(struct xa_state *, unsigned long max, xa_mark_t);
|
| 1523 | void xas_init_marks(const struct xa_state *);
|
| 1524 |
|
| 1525 | bool xas_nomem(struct xa_state *, gfp_t);
|
| 1526 | void xas_destroy(struct xa_state *);
|
| 1527 | void xas_pause(struct xa_state *);
|
| 1528 |
|
| 1529 | void xas_create_range(struct xa_state *);
|
| 1530 |
|
| 1531 | #ifdef CONFIG_XARRAY_MULTI
|
| 1532 | int xa_get_order(struct xarray *, unsigned long index);
|
| 1533 | void xas_split(struct xa_state *, void *entry, unsigned int order);
|
| 1534 | void xas_split_alloc(struct xa_state *, void *entry, unsigned int order, gfp_t);
|
| 1535 | #else
|
| 1536 | static inline int xa_get_order(struct xarray *xa, unsigned long index)
|
| 1537 | {
|
| 1538 | return 0;
|
| 1539 | }
|
| 1540 |
|
| 1541 | static inline void xas_split(struct xa_state *xas, void *entry,
|
| 1542 | unsigned int order)
|
| 1543 | {
|
| 1544 | xas_store(xas, entry);
|
| 1545 | }
|
| 1546 |
|
| 1547 | static inline void xas_split_alloc(struct xa_state *xas, void *entry,
|
| 1548 | unsigned int order, gfp_t gfp)
|
| 1549 | {
|
| 1550 | }
|
| 1551 | #endif
|
| 1552 |
|
| 1553 | |
| 1554 | * xas_reload() - Refetch an entry from the xarray.
|
| 1555 | * @xas: XArray operation state.
|
| 1556 | *
|
| 1557 | * Use this function to check that a previously loaded entry still has
|
| 1558 | * the same value. This is useful for the lockless pagecache lookup where
|
| 1559 | * we walk the array with only the RCU lock to protect us, lock the page,
|
| 1560 | * then check that the page hasn't moved since we looked it up.
|
| 1561 | *
|
| 1562 | * The caller guarantees that @xas is still valid. If it may be in an
|
| 1563 | * error or restart state, call xas_load() instead.
|
| 1564 | *
|
| 1565 | * Return: The entry at this location in the xarray.
|
| 1566 |
|
| 1567 | static inline void *xas_reload(struct xa_state *xas)
|
| 1568 | {
|
| 1569 | struct xa_node *node = xas->xa_node;
|
| 1570 | void *entry;
|
| 1571 | char offset;
|
| 1572 |
|
| 1573 | if (!node)
|
| 1574 | return xa_head(xas->xa);
|
| 1575 | if (IS_ENABLED(CONFIG_XARRAY_MULTI)) {
|
| 1576 | offset = (xas->xa_index >> node->shift) & XA_CHUNK_MASK;
|
| 1577 | entry = xa_entry(xas->xa, node, offset);
|
| 1578 | if (!xa_is_sibling(entry))
|
| 1579 | return entry;
|
| 1580 | offset = xa_to_sibling(entry);
|
| 1581 | } else {
|
| 1582 | offset = xas->xa_offset;
|
| 1583 | }
|
| 1584 | return xa_entry(xas->xa, node, offset);
|
| 1585 | }
|
| 1586 |
|
| 1587 | |
| 1588 | * xas_set() - Set up XArray operation state for a different index.
|
| 1589 | * @xas: XArray operation state.
|
| 1590 | * @index: New index into the XArray.
|
| 1591 | *
|
| 1592 | * Move the operation state to refer to a different index. This will
|
| 1593 | * have the effect of starting a walk from the top; see xas_next()
|
| 1594 | * to move to an adjacent index.
|
| 1595 |
|
| 1596 | static inline void xas_set(struct xa_state *xas, unsigned long index)
|
| 1597 | {
|
| 1598 | xas->xa_index = index;
|
| 1599 | xas->xa_node = XAS_RESTART;
|
| 1600 | }
|
| 1601 |
|
| 1602 | |
| 1603 | * xas_advance() - Skip over sibling entries.
|
| 1604 | * @xas: XArray operation state.
|
| 1605 | * @index: Index of last sibling entry.
|
| 1606 | *
|
| 1607 | * Move the operation state to refer to the last sibling entry.
|
| 1608 | * This is useful for loops that normally want to see sibling
|
| 1609 | * entries but sometimes want to skip them. Use xas_set() if you
|
| 1610 | * want to move to an index which is not part of this entry.
|
| 1611 |
|
| 1612 | static inline void xas_advance(struct xa_state *xas, unsigned long index)
|
| 1613 | {
|
| 1614 | unsigned char shift = xas_is_node(xas) ? xas->xa_node->shift : 0;
|
| 1615 |
|
| 1616 | xas->xa_index = index;
|
| 1617 | xas->xa_offset = (index >> shift) & XA_CHUNK_MASK;
|
| 1618 | }
|
| 1619 |
|
| 1620 | |
| 1621 | * xas_set_order() - Set up XArray operation state for a multislot entry.
|
| 1622 | * @xas: XArray operation state.
|
| 1623 | * @index: Target of the operation.
|
| 1624 | * @order: Entry occupies 2^@order indices.
|
| 1625 |
|
| 1626 | static inline void xas_set_order(struct xa_state *xas, unsigned long index,
|
| 1627 | unsigned int order)
|
| 1628 | {
|
| 1629 | #ifdef CONFIG_XARRAY_MULTI
|
| 1630 | xas->xa_index = order < BITS_PER_LONG ? (index >> order) << order : 0;
|
| 1631 | xas->xa_shift = order - (order % XA_CHUNK_SHIFT);
|
| 1632 | xas->xa_sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1;
|
| 1633 | xas->xa_node = XAS_RESTART;
|
| 1634 | #else
|
| 1635 | BUG_ON(order > 0);
|
| 1636 | xas_set(xas, index);
|
| 1637 | #endif
|
| 1638 | }
|
| 1639 |
|
| 1640 | |
| 1641 | * xas_set_update() - Set up XArray operation state for a callback.
|
| 1642 | * @xas: XArray operation state.
|
| 1643 | * @update: Function to call when updating a node.
|
| 1644 | *
|
| 1645 | * The XArray can notify a caller after it has updated an xa_node.
|
| 1646 | * This is advanced functionality and is only needed by the page
|
| 1647 | * cache and swap cache.
|
| 1648 |
|
| 1649 | static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update)
|
| 1650 | {
|
| 1651 | xas->xa_update = update;
|
| 1652 | }
|
| 1653 |
|
| 1654 | static inline void xas_set_lru(struct xa_state *xas, struct list_lru *lru)
|
| 1655 | {
|
| 1656 | xas->xa_lru = lru;
|
| 1657 | }
|
| 1658 |
|
| 1659 | |
| 1660 | * xas_next_entry() - Advance iterator to next present entry.
|
| 1661 | * @xas: XArray operation state.
|
| 1662 | * @max: Highest index to return.
|
| 1663 | *
|
| 1664 | * xas_next_entry() is an inline function to optimise xarray traversal for
|
| 1665 | * speed. It is equivalent to calling xas_find(), and will call xas_find()
|
| 1666 | * for all the hard cases.
|
| 1667 | *
|
| 1668 | * Return: The next present entry after the one currently referred to by @xas.
|
| 1669 |
|
| 1670 | static inline void *xas_next_entry(struct xa_state *xas, unsigned long max)
|
| 1671 | {
|
| 1672 | struct xa_node *node = xas->xa_node;
|
| 1673 | void *entry;
|
| 1674 |
|
| 1675 | if (unlikely(xas_not_node(node) || node->shift ||
|
| 1676 | xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK)))
|
| 1677 | return xas_find(xas, max);
|
| 1678 |
|
| 1679 | do {
|
| 1680 | if (unlikely(xas->xa_index >= max))
|
| 1681 | return xas_find(xas, max);
|
| 1682 | if (unlikely(xas->xa_offset == XA_CHUNK_MASK))
|
| 1683 | return xas_find(xas, max);
|
| 1684 | entry = xa_entry(xas->xa, node, xas->xa_offset + 1);
|
| 1685 | if (unlikely(xa_is_internal(entry)))
|
| 1686 | return xas_find(xas, max);
|
| 1687 | xas->xa_offset++;
|
| 1688 | xas->xa_index++;
|
| 1689 | } while (!entry);
|
| 1690 |
|
| 1691 | return entry;
|
| 1692 | }
|
| 1693 |
|
| 1694 |
|
| 1695 | static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance,
|
| 1696 | xa_mark_t mark)
|
| 1697 | {
|
| 1698 | unsigned long *addr = xas->xa_node->marks[(__force unsigned)mark];
|
| 1699 | unsigned int offset = xas->xa_offset;
|
| 1700 |
|
| 1701 | if (advance)
|
| 1702 | offset++;
|
| 1703 | if (XA_CHUNK_SIZE == BITS_PER_LONG) {
|
| 1704 | if (offset < XA_CHUNK_SIZE) {
|
| 1705 | unsigned long data = *addr & (~0UL << offset);
|
| 1706 | if (data)
|
| 1707 | return __ffs(data);
|
| 1708 | }
|
| 1709 | return XA_CHUNK_SIZE;
|
| 1710 | }
|
| 1711 |
|
| 1712 | return find_next_bit(addr, XA_CHUNK_SIZE, offset);
|
| 1713 | }
|
| 1714 |
|
| 1715 | |
| 1716 | * xas_next_marked() - Advance iterator to next marked entry.
|
| 1717 | * @xas: XArray operation state.
|
| 1718 | * @max: Highest index to return.
|
| 1719 | * @mark: Mark to search for.
|
| 1720 | *
|
| 1721 | * xas_next_marked() is an inline function to optimise xarray traversal for
|
| 1722 | * speed. It is equivalent to calling xas_find_marked(), and will call
|
| 1723 | * xas_find_marked() for all the hard cases.
|
| 1724 | *
|
| 1725 | * Return: The next marked entry after the one currently referred to by @xas.
|
| 1726 |
|
| 1727 | static inline void *xas_next_marked(struct xa_state *xas, unsigned long max,
|
| 1728 | xa_mark_t mark)
|
| 1729 | {
|
| 1730 | struct xa_node *node = xas->xa_node;
|
| 1731 | void *entry;
|
| 1732 | unsigned int offset;
|
| 1733 |
|
| 1734 | if (unlikely(xas_not_node(node) || node->shift))
|
| 1735 | return xas_find_marked(xas, max, mark);
|
| 1736 | offset = xas_find_chunk(xas, true, mark);
|
| 1737 | xas->xa_offset = offset;
|
| 1738 | xas->xa_index = (xas->xa_index & ~XA_CHUNK_MASK) + offset;
|
| 1739 | if (xas->xa_index > max)
|
| 1740 | return NULL;
|
| 1741 | if (offset == XA_CHUNK_SIZE)
|
| 1742 | return xas_find_marked(xas, max, mark);
|
| 1743 | entry = xa_entry(xas->xa, node, offset);
|
| 1744 | if (!entry)
|
| 1745 | return xas_find_marked(xas, max, mark);
|
| 1746 | return entry;
|
| 1747 | }
|
| 1748 |
|
| 1749 | |
| 1750 | * If iterating while holding a lock, drop the lock and reschedule
|
| 1751 | * every %XA_CHECK_SCHED loops.
|
| 1752 |
|
| 1753 | enum {
|
| 1754 | XA_CHECK_SCHED = 4096,
|
| 1755 | };
|
| 1756 |
|
| 1757 | |
| 1758 | * xas_for_each() - Iterate over a range of an XArray.
|
| 1759 | * @xas: XArray operation state.
|
| 1760 | * @entry: Entry retrieved from the array.
|
| 1761 | * @max: Maximum index to retrieve from array.
|
| 1762 | *
|
| 1763 | * The loop body will be executed for each entry present in the xarray
|
| 1764 | * between the current xas position and @max. @entry will be set to
|
| 1765 | * the entry retrieved from the xarray. It is safe to delete entries
|
| 1766 | * from the array in the loop body. You should hold either the RCU lock
|
| 1767 | * or the xa_lock while iterating. If you need to drop the lock, call
|
| 1768 | * xas_pause() first.
|
| 1769 |
|
| 1770 | #define xas_for_each(xas, entry, max) \
|
| 1771 | for (entry = xas_find(xas, max); entry; \
|
| 1772 | entry = xas_next_entry(xas, max))
|
| 1773 |
|
| 1774 | |
| 1775 | * xas_for_each_marked() - Iterate over a range of an XArray.
|
| 1776 | * @xas: XArray operation state.
|
| 1777 | * @entry: Entry retrieved from the array.
|
| 1778 | * @max: Maximum index to retrieve from array.
|
| 1779 | * @mark: Mark to search for.
|
| 1780 | *
|
| 1781 | * The loop body will be executed for each marked entry in the xarray
|
| 1782 | * between the current xas position and @max. @entry will be set to
|
| 1783 | * the entry retrieved from the xarray. It is safe to delete entries
|
| 1784 | * from the array in the loop body. You should hold either the RCU lock
|
| 1785 | * or the xa_lock while iterating. If you need to drop the lock, call
|
| 1786 | * xas_pause() first.
|
| 1787 |
|
| 1788 | #define xas_for_each_marked(xas, entry, max, mark) \
|
| 1789 | for (entry = xas_find_marked(xas, max, mark); entry; \
|
| 1790 | entry = xas_next_marked(xas, max, mark))
|
| 1791 |
|
| 1792 | |
| 1793 | * xas_for_each_conflict() - Iterate over a range of an XArray.
|
| 1794 | * @xas: XArray operation state.
|
| 1795 | * @entry: Entry retrieved from the array.
|
| 1796 | *
|
| 1797 | * The loop body will be executed for each entry in the XArray that
|
| 1798 | * lies within the range specified by @xas. If the loop terminates
|
| 1799 | * normally, @entry will be %NULL. The user may break out of the loop,
|
| 1800 | * which will leave @entry set to the conflicting entry. The caller
|
| 1801 | * may also call xa_set_err() to exit the loop while setting an error
|
| 1802 | * to record the reason.
|
| 1803 |
|
| 1804 | #define xas_for_each_conflict(xas, entry) \
|
| 1805 | while ((entry = xas_find_conflict(xas)))
|
| 1806 |
|
| 1807 | void *__xas_next(struct xa_state *);
|
| 1808 | void *__xas_prev(struct xa_state *);
|
| 1809 |
|
| 1810 | |
| 1811 | * xas_prev() - Move iterator to previous index.
|
| 1812 | * @xas: XArray operation state.
|
| 1813 | *
|
| 1814 | * If the @xas was in an error state, it will remain in an error state
|
| 1815 | * and this function will return %NULL. If the @xas has never been walked,
|
| 1816 | * it will have the effect of calling xas_load(). Otherwise one will be
|
| 1817 | * subtracted from the index and the state will be walked to the correct
|
| 1818 | * location in the array for the next operation.
|
| 1819 | *
|
| 1820 | * If the iterator was referencing index 0, this function wraps
|
| 1821 | * around to %ULONG_MAX.
|
| 1822 | *
|
| 1823 | * Return: The entry at the new index. This may be %NULL or an internal
|
| 1824 | * entry.
|
| 1825 |
|
| 1826 | static inline void *xas_prev(struct xa_state *xas)
|
| 1827 | {
|
| 1828 | struct xa_node *node = xas->xa_node;
|
| 1829 |
|
| 1830 | if (unlikely(xas_not_node(node) || node->shift ||
|
| 1831 | xas->xa_offset == 0))
|
| 1832 | return __xas_prev(xas);
|
| 1833 |
|
| 1834 | xas->xa_index--;
|
| 1835 | xas->xa_offset--;
|
| 1836 | return xa_entry(xas->xa, node, xas->xa_offset);
|
| 1837 | }
|
| 1838 |
|
| 1839 | |
| 1840 | * xas_next() - Move state to next index.
|
| 1841 | * @xas: XArray operation state.
|
| 1842 | *
|
| 1843 | * If the @xas was in an error state, it will remain in an error state
|
| 1844 | * and this function will return %NULL. If the @xas has never been walked,
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| 1845 | * it will have the effect of calling xas_load(). Otherwise one will be
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| 1846 | * added to the index and the state will be walked to the correct
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| 1847 | * location in the array for the next operation.
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| 1848 | *
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| 1849 | * If the iterator was referencing index %ULONG_MAX, this function wraps
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| 1850 | * around to 0.
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| 1851 | *
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| 1852 | * Return: The entry at the new index. This may be %NULL or an internal
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| 1853 | * entry.
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| 1854 |
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| 1855 | static inline void *xas_next(struct xa_state *xas)
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| 1856 | {
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| 1857 | struct xa_node *node = xas->xa_node;
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| 1858 |
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| 1859 | if (unlikely(xas_not_node(node) || node->shift ||
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| 1860 | xas->xa_offset == XA_CHUNK_MASK))
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| 1861 | return __xas_next(xas);
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| 1862 |
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| 1863 | xas->xa_index++;
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| 1864 | xas->xa_offset++;
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| 1865 | return xa_entry(xas->xa, node, xas->xa_offset);
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| 1866 | }
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| 1867 |
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| 1868 | #endif
|