From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: Pavel Begunkov <asml.silence@gmail.com>, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 13/13] io_uring: don't wait when under-submitting
Date: Wed, 18 Dec 2019 10:18:35 -0700 [thread overview]
Message-ID: <20191218171835.13315-14-axboe@kernel.dk> (raw)
In-Reply-To: <20191218171835.13315-1-axboe@kernel.dk>
From: Pavel Begunkov <asml.silence@gmail.com>
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 <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 74dc9de94117..b7800def3090 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5133,6 +5133,9 @@ 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;
@@ -5146,6 +5149,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
}
}
+out:
percpu_ref_put(&ctx->refs);
out_fput:
fdput(f);
--
2.24.1
prev parent reply other threads:[~2019-12-18 17:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 17:18 [PATCHSET v3] io_uring fixes for 5.5-rc3 Jens Axboe
2019-12-18 17:18 ` [PATCH 01/13] io_uring: fix stale comment and a few typos Jens Axboe
2019-12-18 17:18 ` [PATCH 02/13] io_uring: fix sporadic -EFAULT from IORING_OP_RECVMSG Jens Axboe
2019-12-18 17:18 ` [PATCH 03/13] io-wq: re-add io_wq_current_is_worker() Jens Axboe
2019-12-18 17:18 ` [PATCH 04/13] io_uring: fix pre-prepped issue with force_nonblock == true Jens Axboe
2019-12-18 17:18 ` [PATCH 05/13] io_uring: remove 'sqe' parameter to the OP helpers that take it Jens Axboe
2019-12-18 17:18 ` [PATCH 06/13] io_uring: any deferred command must have stable sqe data Jens Axboe
2019-12-18 17:18 ` [PATCH 07/13] io_uring: make HARDLINK imply LINK Jens Axboe
2019-12-18 17:18 ` [PATCH 08/13] io_uring: make IORING_POLL_ADD and IORING_POLL_REMOVE deferrable Jens Axboe
2019-12-18 17:18 ` [PATCH 09/13] io_uring: make IORING_OP_CANCEL_ASYNC deferrable Jens Axboe
2019-12-18 17:18 ` [PATCH 10/13] io_uring: make IORING_OP_TIMEOUT_REMOVE deferrable Jens Axboe
2019-12-18 17:18 ` [PATCH 11/13] io_uring: read opcode and user_data from SQE exactly once Jens Axboe
2019-12-18 17:18 ` [PATCH 12/13] io_uring: warn about unhandled opcode Jens Axboe
2019-12-18 17:18 ` Jens Axboe [this message]
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