diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index 6d9a53d..5355f8f 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -189,14 +189,14 @@ static __always_inline u64 field_mask(u64 field) } #define field_max(field) ((typeof(field))field_mask(field)) #define ____MAKE_OP(type,base,to,from) \ -static __always_inline __##type type##_encode_bits(base v, base field) \ +static __always_inline __##type __must_check type##_encode_bits(base v, base field) \ { \ if (__builtin_constant_p(v) && (v & ~field_mask(field))) \ __field_overflow(); \ return to((v & field_mask(field)) * field_multiplier(field)); \ } \ -static __always_inline __##type type##_replace_bits(__##type old, \ - base val, base field) \ +static __always_inline __##type __must_check type##_replace_bits(__##type old, \ + base val, base field) \ { \ return (old & ~to(field)) | type##_encode_bits(val, field); \ } \ @@ -205,7 +205,7 @@ static __always_inline void type##p_replace_bits(__##type *p, \ { \ *p = (*p & ~to(field)) | type##_encode_bits(val, field); \ } \ -static __always_inline base type##_get_bits(__##type v, base field) \ +static __always_inline base __must_check type##_get_bits(__##type v, base field) \ { \ return (from(v) & field)/field_multiplier(field); \ } diff --git a/include/linux/bits.h b/include/linux/bits.h index 7ad0562..a40cc86 100644 --- a/include/linux/bits.h +++ b/include/linux/bits.h @@ -2,10 +2,8 @@ #ifndef __LINUX_BITS_H #define __LINUX_BITS_H -#include #include #include -#include #define BIT_MASK(nr) (UL(1) << ((nr) % BITS_PER_LONG)) #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) @@ -50,10 +48,14 @@ (type_max(t) << (l) & \ type_max(t) >> (BITS_PER_TYPE(t) - 1 - (h))))) +#define GENMASK(h, l) GENMASK_TYPE(unsigned long, h, l) +#define GENMASK_ULL(h, l) GENMASK_TYPE(unsigned long long, h, l) + #define GENMASK_U8(h, l) GENMASK_TYPE(u8, h, l) #define GENMASK_U16(h, l) GENMASK_TYPE(u16, h, l) #define GENMASK_U32(h, l) GENMASK_TYPE(u32, h, l) #define GENMASK_U64(h, l) GENMASK_TYPE(u64, h, l) +#define GENMASK_U128(h, l) GENMASK_TYPE(u128, h, l) /* * Fixed-type variants of BIT(), with additional checks like GENMASK_TYPE(). The @@ -79,28 +81,9 @@ * BUILD_BUG_ON_ZERO is not available in h files included from asm files, * disable the input check if that is the case. */ -#define GENMASK_INPUT_CHECK(h, l) 0 +#define GENMASK(h, l) __GENMASK(h, l) +#define GENMASK_ULL(h, l) __GENMASK_ULL(h, l) #endif /* !defined(__ASSEMBLY__) */ -#define GENMASK(h, l) \ - (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l)) -#define GENMASK_ULL(h, l) \ - (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l)) - -#if !defined(__ASSEMBLY__) -/* - * Missing asm support - * - * __GENMASK_U128() depends on _BIT128() which would not work - * in the asm code, as it shifts an 'unsigned __int128' data - * type instead of direct representation of 128 bit constants - * such as long and unsigned long. The fundamental problem is - * that a 128 bit constant will get silently truncated by the - * gcc compiler. - */ -#define GENMASK_U128(h, l) \ - (GENMASK_INPUT_CHECK(h, l) + __GENMASK_U128(h, l)) -#endif - #endif /* __LINUX_BITS_H */ diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index ede95bb..ff8f41a 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -355,6 +355,18 @@ unsigned int cpumask_next_wrap(int n, const struct cpumask *src) } /** + * cpumask_random - get random cpu in *src. + * @src: cpumask pointer + * + * Return: random set bit, or >= nr_cpu_ids if @src is empty. + */ +static __always_inline +unsigned int cpumask_random(const struct cpumask *src) +{ + return find_random_bit(cpumask_bits(src), nr_cpu_ids); +} + +/** * for_each_cpu - iterate over every cpu in a mask * @cpu: the (optionally unsigned) integer iterator * @mask: the cpumask pointer @@ -547,22 +559,6 @@ unsigned int cpumask_nth_and(unsigned int cpu, const struct cpumask *srcp1, } /** - * cpumask_nth_andnot - get the Nth cpu set in 1st cpumask, and clear in 2nd. - * @srcp1: the cpumask pointer - * @srcp2: the cpumask pointer - * @cpu: the Nth cpu to find, starting from 0 - * - * Return: >= nr_cpu_ids if such cpu doesn't exist. - */ -static __always_inline -unsigned int cpumask_nth_andnot(unsigned int cpu, const struct cpumask *srcp1, - const struct cpumask *srcp2) -{ - return find_nth_andnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), - small_cpumask_bits, cpumask_check(cpu)); -} - -/** * cpumask_nth_and_andnot - get the Nth cpu set in 1st and 2nd cpumask, and clear in 3rd. * @srcp1: the cpumask pointer * @srcp2: the cpumask pointer diff --git a/include/linux/find.h b/include/linux/find.h index 5a2c267..9d720ad 100644 --- a/include/linux/find.h +++ b/include/linux/find.h @@ -44,6 +44,8 @@ unsigned long _find_next_bit_le(const unsigned long *addr, unsigned long size, unsigned long offset); #endif +unsigned long find_random_bit(const unsigned long *addr, unsigned long size); + #ifndef find_next_bit /** * find_next_bit - find the next set bit in a memory region @@ -268,33 +270,6 @@ unsigned long find_nth_and_bit(const unsigned long *addr1, const unsigned long * } /** - * find_nth_andnot_bit - find N'th set bit in 2 memory regions, - * flipping bits in 2nd region - * @addr1: The 1st address to start the search at - * @addr2: The 2nd address to start the search at - * @size: The maximum number of bits to search - * @n: The number of set bit, which position is needed, counting from 0 - * - * Returns the bit number of the N'th set bit. - * If no such, returns @size. - */ -static __always_inline -unsigned long find_nth_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, - unsigned long size, unsigned long n) -{ - if (n >= size) - return size; - - if (small_const_nbits(size)) { - unsigned long val = *addr1 & (~*addr2) & GENMASK(size - 1, 0); - - return val ? fns(val, n) : size; - } - - return __find_nth_andnot_bit(addr1, addr2, size, n); -} - -/** * find_nth_and_andnot_bit - find N'th set bit in 2 memory regions, * excluding those set in 3rd region * @addr1: The 1st address to start the search at diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index f08ae71..7ad1f5c 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -492,21 +492,9 @@ static __always_inline int num_node_state(enum node_states state) static __always_inline int node_random(const nodemask_t *maskp) { #if defined(CONFIG_NUMA) && (MAX_NUMNODES > 1) - int w, bit; - - w = nodes_weight(*maskp); - switch (w) { - case 0: - bit = NUMA_NO_NODE; - break; - case 1: - bit = first_node(*maskp); - break; - default: - bit = find_nth_bit(maskp->bits, MAX_NUMNODES, get_random_u32_below(w)); - break; - } - return bit; + int node = find_random_bit(maskp->bits, MAX_NUMNODES); + + return node < MAX_NUMNODES ? node : NUMA_NO_NODE; #else return 0; #endif diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index e400fe1..0aef0e3 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -340,10 +340,7 @@ static void clocksource_verify_choose_cpus(void) * CPUs that are currently online. */ for (i = 1; i < n; i++) { - cpu = get_random_u32_below(nr_cpu_ids); - cpu = cpumask_next(cpu - 1, cpu_online_mask); - if (cpu >= nr_cpu_ids) - cpu = cpumask_first(cpu_online_mask); + cpu = cpumask_random(cpu_online_mask); if (!WARN_ON_ONCE(cpu >= nr_cpu_ids)) cpumask_set_cpu(cpu, &cpus_chosen); } diff --git a/kernel/watchdog_buddy.c b/kernel/watchdog_buddy.c index 34dbfe0..ee754d7 100644 --- a/kernel/watchdog_buddy.c +++ b/kernel/watchdog_buddy.c @@ -12,10 +12,7 @@ static unsigned int watchdog_next_cpu(unsigned int cpu) { unsigned int next_cpu; - next_cpu = cpumask_next(cpu, &watchdog_cpus); - if (next_cpu >= nr_cpu_ids) - next_cpu = cpumask_first(&watchdog_cpus); - + next_cpu = cpumask_next_wrap(cpu, &watchdog_cpus); if (next_cpu == cpu) return nr_cpu_ids; diff --git a/lib/find_bit.c b/lib/find_bit.c index 06b6342..d4b5a29 100644 --- a/lib/find_bit.c +++ b/lib/find_bit.c @@ -18,6 +18,7 @@ #include #include #include +#include /* * Common helper for find_bit() function family @@ -291,3 +292,26 @@ EXPORT_SYMBOL(_find_next_bit_le); #endif #endif /* __BIG_ENDIAN */ + +/** + * find_random_bit - find a set bit at random position + * @addr: The address to base the search on + * @size: The bitmap size in bits + * + * Returns: a position of a random set bit; >= @size otherwise + */ +unsigned long find_random_bit(const unsigned long *addr, unsigned long size) +{ + int w = bitmap_weight(addr, size); + + switch (w) { + case 0: + return size; + case 1: + /* Performance trick for single-bit bitmaps */ + return find_first_bit(addr, size); + default: + return find_nth_bit(addr, size, get_random_u32_below(w)); + } +} +EXPORT_SYMBOL(find_random_bit); diff --git a/lib/tests/test_bits.c b/lib/tests/test_bits.c index 47325b4..ab88e50 100644 --- a/lib/tests/test_bits.c +++ b/lib/tests/test_bits.c @@ -26,6 +26,23 @@ static_assert(assert_type(u16, GENMASK_U16(15, 0)) == U16_MAX); static_assert(assert_type(u32, GENMASK_U32(31, 0)) == U32_MAX); static_assert(assert_type(u64, GENMASK_U64(63, 0)) == U64_MAX); +/* FIXME: add a test case written in asm for GENMASK() and GENMASK_ULL() */ + +static void __genmask_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, 1ul, __GENMASK(0, 0)); + KUNIT_EXPECT_EQ(test, 3ul, __GENMASK(1, 0)); + KUNIT_EXPECT_EQ(test, 6ul, __GENMASK(2, 1)); + KUNIT_EXPECT_EQ(test, 0xFFFFFFFFul, __GENMASK(31, 0)); +} + +static void __genmask_ull_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, 1ull, __GENMASK_ULL(0, 0)); + KUNIT_EXPECT_EQ(test, 3ull, __GENMASK_ULL(1, 0)); + KUNIT_EXPECT_EQ(test, 0x000000ffffe00000ull, __GENMASK_ULL(39, 21)); + KUNIT_EXPECT_EQ(test, 0xffffffffffffffffull, __GENMASK_ULL(63, 0)); +} static void genmask_test(struct kunit *test) { @@ -123,6 +140,8 @@ static void genmask_input_check_test(struct kunit *test) static struct kunit_case bits_test_cases[] = { + KUNIT_CASE(__genmask_test), + KUNIT_CASE(__genmask_ull_test), KUNIT_CASE(genmask_test), KUNIT_CASE(genmask_ull_test), KUNIT_CASE(genmask_u128_test),