Commit ab0f2473 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'io_uring-5.8-2020-06-26' of git://git.kernel.dk/linux-block 

Pull io_uring fixes from Jens Axboe:
 "Three small fixes:

   - Close a corner case for polled IO resubmission (Pavel)

   - Toss commands when exiting (Pavel)

   - Fix SQPOLL conditional reschedule on perpetually busy submit
     (Xuan)"

* tag 'io_uring-5.8-2020-06-26' of git://git.kernel.dk/linux-block:
  io_uring: fix current->mm NULL dereference on exit
  io_uring: fix hanging iopoll in case of -EAGAIN
  io_uring: fix io_sq_thread no schedule when busy
parents 9b8d0207 d60b5fbc

fs/io_uring.c

+13 −9
Original line number Diff line number Diff line
@@ -890,6 +890,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, 
				 struct io_uring_files_update *ip,

				 unsigned nr_args);

static int io_grab_files(struct io_kiocb *req);

static void io_complete_rw_common(struct kiocb *kiocb, long res);

static void io_cleanup_req(struct io_kiocb *req);

static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,

		       int fd, struct file **out_file, bool fixed);
@@ -1749,6 +1750,14 @@ static void io_iopoll_queue(struct list_head *again) 
	do {

		req = list_first_entry(again, struct io_kiocb, list);

		list_del(&req->list);



		/* shouldn't happen unless io_uring is dying, cancel reqs */

		if (unlikely(!current->mm)) {

			io_complete_rw_common(&req->rw.kiocb, -EAGAIN);

			io_put_req(req);

			continue;

		}



		refcount_inc(&req->refs);

		io_queue_async_work(req);

	} while (!list_empty(again));
@@ -1994,11 +2003,9 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) 


	WRITE_ONCE(req->result, res);

	/* order with io_poll_complete() checking ->result */

	if (res != -EAGAIN) {

	smp_wmb();

	WRITE_ONCE(req->iopoll_completed, 1);

}

}



/*

 * After the iocb has been issued, it's safe to be found on the poll list.
@@ -5353,9 +5360,6 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, 
	if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) {

		const bool in_async = io_wq_current_is_worker();



		if (req->result == -EAGAIN)

			return -EAGAIN;



		/* workqueue context doesn't hold uring_lock, grab it now */

		if (in_async)

			mutex_lock(&ctx->uring_lock);
@@ -6011,7 +6015,7 @@ static int io_sq_thread(void *data) 
		 * If submit got -EBUSY, flag us as needing the application

		 * to enter the kernel to reap and flush events.

		 */

		if (!to_submit || ret == -EBUSY) {

		if (!to_submit || ret == -EBUSY || need_resched()) {

			/*

			 * Drop cur_mm before scheduling, we can't hold it for

			 * long periods (or over schedule()). Do this before
@@ -6027,7 +6031,7 @@ static int io_sq_thread(void *data) 
			 * more IO, we should wait for the application to

			 * reap events and wake us up.

			 */

			if (!list_empty(&ctx->poll_list) ||

			if (!list_empty(&ctx->poll_list) || need_resched() ||

			    (!time_after(jiffies, timeout) && ret != -EBUSY &&

			    !percpu_ref_is_dying(&ctx->refs))) {

				if (current->task_works)

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