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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
	[email protected], Jens Axboe <[email protected]>
Subject: [PATCH 1/9] io_uring: consider any io_read/write -EAGAIN as final
Date: Thu, 20 Feb 2020 13:31:43 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

If the -EAGAIN happens because of a static condition, then a poll
or later retry won't fix it. We must call it again from blocking
condition. Play it safe and ensure that any -EAGAIN condition from read
or write must retry from async context.

Signed-off-by: Jens Axboe <[email protected]>
---
 fs/io_uring.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6e249aa97ba3..bd3a39b0f4ee 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2255,10 +2255,8 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
 	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
 	 * we know to async punt it even if it was opened O_NONBLOCK
 	 */
-	if (force_nonblock && !io_file_supports_async(req->file)) {
-		req->flags |= REQ_F_MUST_PUNT;
+	if (force_nonblock && !io_file_supports_async(req->file))
 		goto copy_iov;
-	}
 
 	iov_count = iov_iter_count(&iter);
 	ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count);
@@ -2279,6 +2277,8 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
 						inline_vecs, &iter);
 			if (ret)
 				goto out_free;
+			/* any defer here is final, must blocking retry */
+			req->flags |= REQ_F_MUST_PUNT;
 			return -EAGAIN;
 		}
 	}
@@ -2344,10 +2344,8 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
 	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
 	 * we know to async punt it even if it was opened O_NONBLOCK
 	 */
-	if (force_nonblock && !io_file_supports_async(req->file)) {
-		req->flags |= REQ_F_MUST_PUNT;
+	if (force_nonblock && !io_file_supports_async(req->file))
 		goto copy_iov;
-	}
 
 	/* file path doesn't support NOWAIT for non-direct_IO */
 	if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
@@ -2392,6 +2390,8 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
 						inline_vecs, &iter);
 			if (ret)
 				goto out_free;
+			/* any defer here is final, must blocking retry */
+			req->flags |= REQ_F_MUST_PUNT;
 			return -EAGAIN;
 		}
 	}
-- 
2.25.1


  reply	other threads:[~2020-02-20 20:31 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-20 20:31 [PATCHSET 0/9] io_uring: use polled async retry Jens Axboe
2020-02-20 20:31 ` Jens Axboe [this message]
2020-02-20 20:31 ` [PATCH 2/9] io_uring: io_accept() should hold on to submit reference on retry Jens Axboe
2020-02-20 20:31 ` [PATCH 3/9] sched: move io-wq/workqueue worker sched in/out into helpers Jens Axboe
2020-02-20 20:31 ` [PATCH 4/9] task_work_run: don't take ->pi_lock unconditionally Jens Axboe
2020-02-20 20:31 ` [PATCH 5/9] kernel: abstract out task work helpers Jens Axboe
2020-02-20 21:07   ` Peter Zijlstra
2020-02-20 21:08     ` Jens Axboe
2020-02-20 20:31 ` [PATCH 6/9] sched: add a sched_work list Jens Axboe
2020-02-20 21:17   ` Peter Zijlstra
2020-02-20 21:53     ` Jens Axboe
2020-02-20 22:02       ` Jens Axboe
2020-02-20 20:31 ` [PATCH 7/9] io_uring: add per-task callback handler Jens Axboe
2020-02-20 22:02   ` Jann Horn
2020-02-20 22:14     ` Jens Axboe
2020-02-20 22:18       ` Jens Axboe
2020-02-20 22:25         ` Jann Horn
2020-02-20 22:23       ` Jens Axboe
2020-02-20 22:38         ` Jann Horn
2020-02-20 22:56           ` Jens Axboe
2020-02-20 22:58             ` Jann Horn
2020-02-20 23:02               ` Jens Axboe
2020-02-20 22:23       ` Jann Horn
2020-02-20 23:00         ` Jens Axboe
2020-02-20 23:12           ` Jann Horn
2020-02-20 23:22             ` Jens Axboe
2020-02-21  1:29               ` Jann Horn
2020-02-21 17:32                 ` Jens Axboe
2020-02-21 19:24                   ` Jann Horn
2020-02-21 20:18                     ` Jens Axboe
2020-02-20 22:56     ` Jann Horn
2020-02-21 10:47     ` Peter Zijlstra
2020-02-21 14:49       ` Jens Axboe
2020-02-21 15:02         ` Jann Horn
2020-02-21 16:12           ` Peter Zijlstra
2020-02-21 16:23         ` Peter Zijlstra
2020-02-21 20:13           ` Jens Axboe
2020-02-21 13:51   ` Pavel Begunkov
2020-02-21 14:50     ` Jens Axboe
2020-02-21 18:30       ` Pavel Begunkov
2020-02-21 19:10         ` Jens Axboe
2020-02-21 19:22           ` Pavel Begunkov
2020-02-23  6:00           ` Jens Axboe
2020-02-23  6:26             ` Jens Axboe
2020-02-23 11:02               ` Pavel Begunkov
2020-02-23 14:49                 ` Jens Axboe
2020-02-23 14:58                   ` Jens Axboe
2020-02-23 15:07                     ` Jens Axboe
2020-02-23 18:04                       ` Pavel Begunkov
2020-02-23 18:06                         ` Jens Axboe
2020-02-23 17:55                   ` Pavel Begunkov
2020-02-20 20:31 ` [PATCH 8/9] io_uring: mark requests that we can do poll async in io_op_defs Jens Axboe
2020-02-20 20:31 ` [PATCH 9/9] io_uring: use poll driven retry for files that support it Jens Axboe

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