Commit 0b81e80c authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: tctx->task_lock should be IRQ safe 



We add task_work from any context, hence we need to ensure that we can
tolerate it being from IRQ context as well.

Fixes: 7cbf1722 ("io_uring: provide FIFO ordering for task_work")
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0d4370cf

fs/io_uring.c

+7 −6
Original line number Diff line number Diff line
@@ -2186,10 +2186,10 @@ static bool __tctx_task_work(struct io_uring_task *tctx) 
	if (wq_list_empty(&tctx->task_list))

		return false;



	spin_lock(&tctx->task_lock);

	spin_lock_irq(&tctx->task_lock);

	list = tctx->task_list;

	INIT_WQ_LIST(&tctx->task_list);

	spin_unlock(&tctx->task_lock);

	spin_unlock_irq(&tctx->task_lock);



	node = list.first;

	while (node) {
@@ -2236,13 +2236,14 @@ static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req, 
{

	struct io_uring_task *tctx = tsk->io_uring;

	struct io_wq_work_node *node, *prev;

	unsigned long flags;

	int ret;



	WARN_ON_ONCE(!tctx);



	spin_lock(&tctx->task_lock);

	spin_lock_irqsave(&tctx->task_lock, flags);

	wq_list_add_tail(&req->io_task_work.node, &tctx->task_list);

	spin_unlock(&tctx->task_lock);

	spin_unlock_irqrestore(&tctx->task_lock, flags);



	/* task_work already pending, we're done */

	if (test_bit(0, &tctx->task_state) ||
@@ -2257,7 +2258,7 @@ static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req, 
	 * in the list, it got run and we're fine.

	 */

	ret = 0;

	spin_lock(&tctx->task_lock);

	spin_lock_irqsave(&tctx->task_lock, flags);

	wq_list_for_each(node, prev, &tctx->task_list) {

		if (&req->io_task_work.node == node) {

			wq_list_del(&tctx->task_list, node, prev);
@@ -2265,7 +2266,7 @@ static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req, 
			break;

		}

	}

	spin_unlock(&tctx->task_lock);

	spin_unlock_irqrestore(&tctx->task_lock, flags);

	clear_bit(0, &tctx->task_state);

	return ret;

}