From 7c504e65206a4379ff38fe41d21b32b6c2c3e53e Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 18 Dec 2019 19:53:45 +0300 Subject: io_uring: don't wait when under-submitting There is no reliable way to submit and wait in a single syscall, as io_submit_sqes() may under-consume sqes (in case of an early error). Then it will wait for not-yet-submitted requests, deadlocking the user in most cases. Don't wait/poll if can't submit all sqes Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs') diff --git a/fs/io_uring.c b/fs/io_uring.c index 1d4e7332ccae..81e7fe6dee18 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5135,6 +5135,9 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, submitted = io_submit_sqes(ctx, to_submit, f.file, fd, &cur_mm, false); mutex_unlock(&ctx->uring_lock); + + if (submitted != to_submit) + goto out; } if (flags & IORING_ENTER_GETEVENTS) { unsigned nr_events = 0; @@ -5148,6 +5151,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, } } +out: percpu_ref_put(&ctx->refs); out_fput: fdput(f); -- cgit v1.2.3-59-g8ed1b