Subject: [PATCH 4.19 025/115] net: make socket read/write_iter() honor IOCB_NOWAIT

From: Greg Kroah-Hartman <[email-masked]>
Date: Tue, 7 Jan 2020 21:53:55 +0100

From: Jens Axboe <[email-masked]>

[ Upstream commit ebfcd8955c0b52eb793bcbc9e71140e3d0cdb228 ]

The socket read/write helpers only look at the file O_NONBLOCK. not
the iocb IOCB_NOWAIT flag. This breaks users like preadv2/pwritev2
and io_uring that rely on not having the file itself marked nonblocking,
but rather the iocb itself.

Cc: [email-masked]
Acked-by: David Miller <[email-masked]>
Signed-off-by: Jens Axboe <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 18d27b8c2511..1290aad5d1c3 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -867,7 +867,7 @@ static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
 			     .msg_iocb = iocb};
 	ssize_t res;
 
-	if (file->f_flags & O_NONBLOCK)
+	if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT))
 		msg.msg_flags = MSG_DONTWAIT;
 
 	if (iocb->ki_pos != 0)
@@ -892,7 +892,7 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (iocb->ki_pos != 0)
 		return -ESPIPE;
 
-	if (file->f_flags & O_NONBLOCK)
+	if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT))
 		msg.msg_flags = MSG_DONTWAIT;
 
 	if (sock->type == SOCK_SEQPACKET)
-- 
2.20.1