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

From: Pavel Begunkov
Date: Fri May 01 2020 - 10:10:59 EST


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@xxxxxxxxx>
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
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