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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-10-07 15:43:04 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-10-07 15:43:04 +0100 |
| commit | a56e74f546b64be93731e42d83baf5b538cc1b11 (patch) | |
| tree | 18f6dee45d801e57ac9db2a31664b0d5c0762c50 /drivers/md/dm-stats.c | |
| parent | d08e2e09042bd3f7ef66a35cb4bb92794ab26bb2 (diff) | |
| parent | e4e7f10bfc4069925e99cc4b428c3434e30b6c3f (diff) | |
Merge branch 'arm-aesbs' of git://git.linaro.org/people/ardbiesheuvel/linux-arm into devel-stable
Diffstat (limited to 'drivers/md/dm-stats.c')
| -rw-r--r-- | drivers/md/dm-stats.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c index 8ae31e8d3d6..3d404c1371e 100644 --- a/drivers/md/dm-stats.c +++ b/drivers/md/dm-stats.c @@ -451,19 +451,26 @@ static void dm_stat_for_entry(struct dm_stat *s, size_t entry, struct dm_stat_percpu *p; /* - * For strict correctness we should use local_irq_disable/enable + * For strict correctness we should use local_irq_save/restore * instead of preempt_disable/enable. * - * This is racy if the driver finishes bios from non-interrupt - * context as well as from interrupt context or from more different - * interrupts. + * preempt_disable/enable is racy if the driver finishes bios + * from non-interrupt context as well as from interrupt context + * or from more different interrupts. * - * However, the race only results in not counting some events, - * so it is acceptable. + * On 64-bit architectures the race only results in not counting some + * events, so it is acceptable. On 32-bit architectures the race could + * cause the counter going off by 2^32, so we need to do proper locking + * there. * * part_stat_lock()/part_stat_unlock() have this race too. */ +#if BITS_PER_LONG == 32 + unsigned long flags; + local_irq_save(flags); +#else preempt_disable(); +#endif p = &s->stat_percpu[smp_processor_id()][entry]; if (!end) { @@ -478,7 +485,11 @@ static void dm_stat_for_entry(struct dm_stat *s, size_t entry, p->ticks[idx] += duration; } +#if BITS_PER_LONG == 32 + local_irq_restore(flags); +#else preempt_enable(); +#endif } static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw, |