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From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, [email protected]
Cc: [email protected]
Subject: [PATCH v2] io_uring: fix short read retries for non-reg files
Date: Thu, 21 Jan 2021 12:01:08 +0000	[thread overview]
Message-ID: <99c647189104206e8391419d8267a82753883bbb.1611230356.git.asml.silence@gmail.com> (raw)

Sockets and other non-regular files may actually expect short reads to
happen, don't retry reads for them. Because non-reg files don't set
FMODE_BUF_RASYNC and so it won't do second/retry do_read, we can filter
out those cases after first do_read() attempt with ret>0.

Cc: [email protected] # 5.9+
Suggested-by: Jens Axboe <[email protected]>
Signed-off-by: Pavel Begunkov <[email protected]>
---

v2: essentially same, but a bit cleaner check placement and
    extended commit message

 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5f6f1e48954e..18920f9785d2 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3552,7 +3552,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 
 	/* read it all, or we did blocking attempt. no retry. */
 	if (!iov_iter_count(iter) || !force_nonblock ||
-	    (req->file->f_flags & O_NONBLOCK))
+	    (req->file->f_flags & O_NONBLOCK) || !(req->flags & REQ_F_ISREG))
 		goto done;
 
 	io_size -= ret;
-- 
2.24.0


             reply	other threads:[~2021-01-21 12:09 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21 12:01 Pavel Begunkov [this message]
2021-01-21 12:41 ` [PATCH v2] io_uring: fix short read retries for non-reg files Jens Axboe

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