[PATCH 1/2] io_uring: remove extra sqpoll submission halting

[Pavel Begunkov <asml.silence@gmail.com>]

SQPOLL task won't submit requests for a context that is currently dying,
so no need to remove ctx from sqd_list prior the main loop of
io_ring_exit_work(). Kill it, will be removed by io_sq_thread_finish()
and only brings confusion and lockups.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e02a18cd287f..fb41725204f0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6744,6 +6744,10 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
 		if (!list_empty(&ctx->iopoll_list))
 			io_do_iopoll(ctx, &nr_events, 0);
 
+		/*
+		 * Don't submit if refs are dying, good for io_uring_register(),
+		 * but also it is relied upon by io_ring_exit_work()
+		 */
 		if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)) &&
 		    !(ctx->flags & IORING_SETUP_R_DISABLED))
 			ret = io_submit_sqes(ctx, to_submit);
@@ -8537,14 +8541,6 @@ static void io_ring_exit_work(struct work_struct *work)
 	struct io_tctx_node *node;
 	int ret;
 
-	/* prevent SQPOLL from submitting new requests */
-	if (ctx->sq_data) {
-		io_sq_thread_park(ctx->sq_data);
-		list_del_init(&ctx->sqd_list);
-		io_sqd_update_thread_idle(ctx->sq_data);
-		io_sq_thread_unpark(ctx->sq_data);
-	}
-
 	/*
 	 * If we're doing polled IO and end up having requests being
 	 * submitted async (out-of-line), then completions can come in while
-- 
2.31.1