Commit 948e1947 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: don't change sqpoll creds if not needed 



SQPOLL doesn't need to change creds if it's not submitting requests.
Move creds overriding into __io_sq_thread() after checking if there are
SQEs pending.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c54368da2357ac539e0a333f7cfff70d5fb045b2.1624543113.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 4ce8ad95

fs/io_uring.c

+7 −7
Original line number Diff line number Diff line
@@ -6803,6 +6803,10 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) 


	if (!list_empty(&ctx->iopoll_list) || to_submit) {

		unsigned nr_events = 0;

		const struct cred *creds = NULL;



		if (ctx->sq_creds != current_cred())

			creds = override_creds(ctx->sq_creds);



		mutex_lock(&ctx->uring_lock);

		if (!list_empty(&ctx->iopoll_list))
@@ -6819,6 +6823,8 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) 


		if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait))

			wake_up(&ctx->sqo_sq_wait);

		if (creds)

			revert_creds(creds);

	}



	return ret;
@@ -6870,7 +6876,6 @@ static int io_sq_thread(void *data) 


	mutex_lock(&sqd->lock);

	while (1) {

		int ret;

		bool cap_entries, sqt_spin, needs_sched;



		if (io_sqd_events_pending(sqd) || signal_pending(current)) {
@@ -6883,13 +6888,8 @@ static int io_sq_thread(void *data) 
		sqt_spin = false;

		cap_entries = !list_is_singular(&sqd->ctx_list);

		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {

			const struct cred *creds = NULL;

			int ret = __io_sq_thread(ctx, cap_entries);



			if (ctx->sq_creds != current_cred())

				creds = override_creds(ctx->sq_creds);

			ret = __io_sq_thread(ctx, cap_entries);

			if (creds)

				revert_creds(creds);

			if (!sqt_spin && (ret > 0 || !list_empty(&ctx->iopoll_list)))

				sqt_spin = true;

		}