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From:   Pavel Begunkov <asml.silence@gmail.com>
To:     Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/4] io_uring: remove setting REQ_F_MUST_PUNT in rw
Date:   Sun, 21 Jun 2020 13:09:50 +0300
Message-Id: <c302765282443434e8a0dc4a83f73bf2b5c7845c.1592733956.git.asml.silence@gmail.com>
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io_{read,write}() {
	...
copy_iov: // prep async
  	if (!(flags & REQ_F_NOWAIT) && !file_can_poll(file))
		flags |= REQ_F_MUST_PUNT;
}

REQ_F_MUST_PUNT there is pointless, because if it happens then
REQ_F_NOWAIT is known to be _not_ set, and the request will go
async path in __io_queue_sqe() anyway. file_can_poll() check
is also repeated in arm_poll*(), so don't need it.

Remove the mentioned assignment REQ_F_MUST_PUNT in preparation
for killing the flag.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 44614571e285..e7ce1608087f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2915,10 +2915,6 @@ static int io_read(struct io_kiocb *req, bool force_nonblock)
 						inline_vecs, &iter);
 			if (ret)
 				goto out;
-			/* any defer here is final, must blocking retry */
-			if (!(req->flags & REQ_F_NOWAIT) &&
-			    !file_can_poll(req->file))
-				req->flags |= REQ_F_MUST_PUNT;
 			/* if we can retry, do so with the callbacks armed */
 			if (io_rw_should_retry(req)) {
 				ret2 = io_iter_do_read(req, &iter);
@@ -3050,10 +3046,6 @@ static int io_write(struct io_kiocb *req, bool force_nonblock)
 						inline_vecs, &iter);
 			if (ret)
 				goto out_free;
-			/* any defer here is final, must blocking retry */
-			if (!(req->flags & REQ_F_NOWAIT) &&
-			    !file_can_poll(req->file))
-				req->flags |= REQ_F_MUST_PUNT;
 			return -EAGAIN;
 		}
 	}
-- 
2.24.0