diff options
| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2011-07-26 16:08:45 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-26 16:49:44 -0700 |
| commit | a64a26e822ddb739de464540dfd2cbb6abce47d5 (patch) | |
| tree | 95d8e783342d64c2c63d98ec5814b4405cab7370 /include/linux/cpumask.h | |
| parent | 37e7b5f1535dddaace865b25df34a2d049a3a66f (diff) | |
| download | lwn-a64a26e822ddb739de464540dfd2cbb6abce47d5.tar.gz lwn-a64a26e822ddb739de464540dfd2cbb6abce47d5.zip | |
cpumask: add cpumask_var_t documentation
cpumask_var_t has one notable difference from cpumask_t. Add the
explanation.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/cpumask.h')
| -rw-r--r-- | include/linux/cpumask.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index b24ac56477b4..4f7a63237471 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -617,6 +617,20 @@ static inline size_t cpumask_size(void) * ... use 'tmpmask' like a normal struct cpumask * ... * * free_cpumask_var(tmpmask); + * + * + * However, one notable exception is there. alloc_cpumask_var() allocates + * only nr_cpumask_bits bits (in the other hand, real cpumask_t always has + * NR_CPUS bits). Therefore you don't have to dereference cpumask_var_t. + * + * cpumask_var_t tmpmask; + * if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL)) + * return -ENOMEM; + * + * var = *tmpmask; + * + * This code makes NR_CPUS length memcopy and brings to a memory corruption. + * cpumask_copy() provide safe copy functionality. */ #ifdef CONFIG_CPUMASK_OFFSTACK typedef struct cpumask *cpumask_var_t; |