Commit 8ec8ba8e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

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
parents 3cf521f7 263782c1

fs/aio.c

+7 −0
Original line number Original line Diff line number Diff line
@@ -830,16 +830,20 @@ void exit_aio(struct mm_struct *mm) 
static void put_reqs_available(struct kioctx *ctx, unsigned nr)

static void put_reqs_available(struct kioctx *ctx, unsigned nr)

{

{

	struct kioctx_cpu *kcpu;

	struct kioctx_cpu *kcpu;

	unsigned long flags;





	preempt_disable();

	preempt_disable();

	kcpu = this_cpu_ptr(ctx->cpu);

	kcpu = this_cpu_ptr(ctx->cpu);





	local_irq_save(flags);

	kcpu->reqs_available += nr;

	kcpu->reqs_available += nr;



	while (kcpu->reqs_available >= ctx->req_batch * 2) {

	while (kcpu->reqs_available >= ctx->req_batch * 2) {

		kcpu->reqs_available -= ctx->req_batch;

		kcpu->reqs_available -= ctx->req_batch;

		atomic_add(ctx->req_batch, &ctx->reqs_available);

		atomic_add(ctx->req_batch, &ctx->reqs_available);

	}

	}





	local_irq_restore(flags);

	preempt_enable();

	preempt_enable();

}

}
@@ -847,10 +851,12 @@ static bool get_reqs_available(struct kioctx *ctx) 
{

{

	struct kioctx_cpu *kcpu;

	struct kioctx_cpu *kcpu;

	bool ret = false;

	bool ret = false;

	unsigned long flags;





	preempt_disable();

	preempt_disable();

	kcpu = this_cpu_ptr(ctx->cpu);

	kcpu = this_cpu_ptr(ctx->cpu);





	local_irq_save(flags);

	if (!kcpu->reqs_available) {

	if (!kcpu->reqs_available) {

		int old, avail = atomic_read(&ctx->reqs_available);

		int old, avail = atomic_read(&ctx->reqs_available);
@@ -869,6 +875,7 @@ static bool get_reqs_available(struct kioctx *ctx) 
	ret = true;

	ret = true;

	kcpu->reqs_available--;

	kcpu->reqs_available--;

out:

out:

	local_irq_restore(flags);

	preempt_enable();

	preempt_enable();

	return ret;

	return ret;

}

}