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Merge git://git.kvack.org/~bcrl/aio-fixes

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Pull another aio fix from Ben LaHaise:
 "put_reqs_available() can now be called from within irq context, which
  means that it (and its sibling function get_reqs_available()) now need
  to be irq-safe, not just preempt-safe"

* git://git.kvack.org/~bcrl/aio-fixes:
  aio: protect reqs_available updates from changes in interrupt handlers
This commit is contained in:
Linus Torvalds 2014-07-14 17:11:50 -07:00
commit 8ec8ba8e7d
1 changed files with 7 additions and 0 deletions
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7
fs/aio.c
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@ -830,16 +830,20 @@ void exit_aio(struct mm_struct *mm)
static void put_reqs_available(struct kioctx *ctx, unsigned nr)
{
struct kioctx_cpu *kcpu;
unsigned long flags;
preempt_disable();
kcpu = this_cpu_ptr(ctx->cpu);
local_irq_save(flags);
kcpu->reqs_available += nr;
while (kcpu->reqs_available >= ctx->req_batch * 2) {
kcpu->reqs_available -= ctx->req_batch;
atomic_add(ctx->req_batch, &ctx->reqs_available);
}
local_irq_restore(flags);
preempt_enable();
}
@ -847,10 +851,12 @@ static bool get_reqs_available(struct kioctx *ctx)
{
struct kioctx_cpu *kcpu;
bool ret = false;
unsigned long flags;
preempt_disable();
kcpu = this_cpu_ptr(ctx->cpu);
local_irq_save(flags);
if (!kcpu->reqs_available) {
int old, avail = atomic_read(&ctx->reqs_available);
@ -869,6 +875,7 @@ static bool get_reqs_available(struct kioctx *ctx)
ret = true;
kcpu->reqs_available--;
out:
local_irq_restore(flags);
preempt_enable();
return ret;
}