From: Alex Shi Subject: [PATCH] cpumask: add a few comments of cpumask functions Date: Mon, 28 May 2012 22:23:51 +0800 Current few cpumask functions' purposes are not quite clear. Stupid user like myself needs to dig into details for clear function purpose and return value. Add few explanation for them is helpful. Thanks for Srivatsa's comments and correction! Signed-off-by: Alex Shi Acked-by: KOSAKI Motohiro Signed-off-by: Rusty Russell --- include/linux/cpumask.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index a2c819d..170c5af 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -271,6 +271,7 @@ static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp) * cpumask_test_cpu - test for a cpu in a cpumask * @cpu: cpu number (< nr_cpu_ids) * @cpumask: the cpumask pointer + * Returns 1 if 'cpu' is set in 'cpumask', else returns 0 * * No static inline type checking - see Subtlety (1) above. */ @@ -281,6 +282,7 @@ static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp) * cpumask_test_and_set_cpu - atomically test and set a cpu in a cpumask * @cpu: cpu number (< nr_cpu_ids) * @cpumask: the cpumask pointer + * Returns 1 if 'cpu' is set in old bitmap of 'cpumask', else returns 0 * * test_and_set_bit wrapper for cpumasks. */ @@ -293,6 +295,7 @@ static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask) * cpumask_test_and_clear_cpu - atomically test and clear a cpu in a cpumask * @cpu: cpu number (< nr_cpu_ids) * @cpumask: the cpumask pointer + * Returns 1 if 'cpu' is set in old bitmap of 'cpumask', else returns 0 * * test_and_clear_bit wrapper for cpumasks. */ @@ -324,6 +327,7 @@ static inline void cpumask_clear(struct cpumask *dstp) * @dstp: the cpumask result * @src1p: the first input * @src2p: the second input + * If *dstp is empty, returns 0, else returns 1 */ static inline int cpumask_and(struct cpumask *dstp, const struct cpumask *src1p, @@ -365,6 +369,7 @@ static inline void cpumask_xor(struct cpumask *dstp, * @dstp: the cpumask result * @src1p: the first input * @src2p: the second input + * If *dstp is empty, returns 0, else returns 1 */ static inline int cpumask_andnot(struct cpumask *dstp, const struct cpumask *src1p, @@ -414,6 +419,7 @@ static inline bool cpumask_intersects(const struct cpumask *src1p, * cpumask_subset - (*src1p & ~*src2p) == 0 * @src1p: the first input * @src2p: the second input + * Returns 1 if *src1p is a subset of *src2p, else returns 0 */ static inline int cpumask_subset(const struct cpumask *src1p, const struct cpumask *src2p)