projects/linux·blob master · refs

158 lines · 3.7 KiB

1// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <linux/errno.h>
4#include <linux/file.h>
5#include <linux/mm.h>
6#include <linux/slab.h>
7#include <linux/nospec.h>
8#include <linux/io_uring.h>
9
10#include <uapi/linux/io_uring.h>
11
12#include "io_uring.h"
13#include "rsrc.h"
14#include "filetable.h"
15
16static int io_file_bitmap_get(struct io_ring_ctx *ctx)
17{
18 struct io_file_table *table = &ctx->file_table;
19 unsigned long nr = ctx->file_alloc_end;
20 int ret;
21
22 if (!table->bitmap)
23 return -ENFILE;
24
25 if (table->alloc_hint < ctx->file_alloc_start ||
26 table->alloc_hint >= ctx->file_alloc_end)
27 table->alloc_hint = ctx->file_alloc_start;
28
29 do {
30 ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint);
31 if (ret != nr)
32 return ret;
33
34 if (table->alloc_hint == ctx->file_alloc_start)
35 break;
36 nr = table->alloc_hint;
37 table->alloc_hint = ctx->file_alloc_start;
38 } while (1);
39
40 return -ENFILE;
41}
42
43bool io_alloc_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table,
44 unsigned nr_files)
45{
46 if (io_rsrc_data_alloc(&table->data, nr_files))
47 return false;
48 table->bitmap = bitmap_zalloc(nr_files, GFP_KERNEL_ACCOUNT);
49 if (table->bitmap)
50 return true;
51 io_rsrc_data_free(ctx, &table->data);
52 return false;
53}
54
55void io_free_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table)
56{
57 io_rsrc_data_free(ctx, &table->data);
58 bitmap_free(table->bitmap);
59 table->bitmap = NULL;
60}
61
62static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file,
63 u32 slot_index)
64 __must_hold(&ctx->uring_lock)
65{
66 struct io_rsrc_node *node;
67
68 if (io_is_uring_fops(file))
69 return -EBADF;
70 if (!ctx->file_table.data.nr)
71 return -ENXIO;
72 if (slot_index >= ctx->file_table.data.nr)
73 return -EINVAL;
74
75 node = io_rsrc_node_alloc(ctx, IORING_RSRC_FILE);
76 if (!node)
77 return -ENOMEM;
78
79 if (!io_reset_rsrc_node(ctx, &ctx->file_table.data, slot_index))
80 io_file_bitmap_set(&ctx->file_table, slot_index);
81
82 ctx->file_table.data.nodes[slot_index] = node;
83 io_fixed_file_set(node, file);
84 return 0;
85}
86
87int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file,
88 unsigned int file_slot)
89{
90 bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
91 int ret;
92
93 if (alloc_slot) {
94 ret = io_file_bitmap_get(ctx);
95 if (unlikely(ret < 0))
96 return ret;
97 file_slot = ret;
98 } else {
99 file_slot--;
100 }
101
102 ret = io_install_fixed_file(ctx, file, file_slot);
103 if (!ret && alloc_slot)
104 ret = file_slot;
105 return ret;
106}
107/*
108 * Note when io_fixed_fd_install() returns error value, it will ensure
109 * fput() is called correspondingly.
110 */
111int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
112 struct file *file, unsigned int file_slot)
113{
114 struct io_ring_ctx *ctx = req->ctx;
115 int ret;
116
117 io_ring_submit_lock(ctx, issue_flags);
118 ret = __io_fixed_fd_install(ctx, file, file_slot);
119 io_ring_submit_unlock(ctx, issue_flags);
120
121 if (unlikely(ret < 0))
122 fput(file);
123 return ret;
124}
125
126int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset)
127{
128 struct io_rsrc_node *node;
129
130 if (unlikely(!ctx->file_table.data.nr))
131 return -ENXIO;
132 if (offset >= ctx->file_table.data.nr)
133 return -EINVAL;
134
135 node = io_rsrc_node_lookup(&ctx->file_table.data, offset);
136 if (!node)
137 return -EBADF;
138 io_reset_rsrc_node(ctx, &ctx->file_table.data, offset);
139 io_file_bitmap_clear(&ctx->file_table, offset);
140 return 0;
141}
142
143int io_register_file_alloc_range(struct io_ring_ctx *ctx,
144 struct io_uring_file_index_range __user *arg)
145{
146 struct io_uring_file_index_range range;
147 u32 end;
148
149 if (copy_from_user(&range, arg, sizeof(range)))
150 return -EFAULT;
151 if (check_add_overflow(range.off, range.len, &end))
152 return -EOVERFLOW;
153 if (range.resv || end > ctx->file_table.data.nr)
154 return -EINVAL;
155
156 io_file_table_set_alloc_range(ctx, range.off, range.len);
157 return 0;
158}