linux-kernel - [PATCH 3/3] io_uring: punt splice async because of inode mtx

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Message-Id: <ca4741da198740647d3d90716d63facf8bc0a53d.1588341674.git.asml.silence@gmail.com>
Date:   Fri,  1 May 2020 17:09:38 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] io_uring: punt splice async because of inode mtx

Nonblocking do_splice() still may wait for some time on an inode mutex.
Let's play safe and always punt it async.

Reported-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 fs/io_uring.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e5d560f2ce12..65458eda2127 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2765,15 +2765,6 @@ static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return 0;
 }
 
-static bool io_splice_punt(struct file *file, int rw)
-{
-	if (get_pipe_info(file))
-		return false;
-	if (!io_file_supports_async(file, rw))
-		return true;
-	return !(file->f_flags & O_NONBLOCK);
-}
-
 static int io_splice(struct io_kiocb *req, bool force_nonblock)
 {
 	struct io_splice *sp = &req->splice;
@@ -2783,11 +2774,8 @@ static int io_splice(struct io_kiocb *req, bool force_nonblock)
 	loff_t *poff_in, *poff_out;
 	long ret;
 
-	if (force_nonblock) {
-		if (io_splice_punt(in, READ) || io_splice_punt(out, WRITE))
-			return -EAGAIN;
-		flags |= SPLICE_F_NONBLOCK;
-	}
+	if (force_nonblock)
+		return -EAGAIN;
 
 	poff_in = (sp->off_in == -1) ? NULL : &sp->off_in;
 	poff_out = (sp->off_out == -1) ? NULL : &sp->off_out;
-- 
2.24.0