Messages in this thread Patch in this message | | | From | KOSAKI Motohiro <> | Subject | [PATCH v2] cpumask: add cpumask_var_t documentation | Date | Fri, 29 Apr 2011 00:27:06 +0900 (JST) |
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cpumask_var_t has one nortable difference against cpumask_t. This patch adds the explanation.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> --- 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 1e40dd0..471c98a 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. cpumask_var_t is allocated + * only nr_cpu_ids 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 bring memroy corruption. + * You have to use cpumask_copy() instead. */ #ifdef CONFIG_CPUMASK_OFFSTACK typedef struct cpumask *cpumask_var_t; -- 1.7.3.1
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