This is a note to let you know that I've just added the patch titled net: make socket read/write_iter() honor IOCB_NOWAIT to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-make-socket-read-write_iter-honor-iocb_nowait.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 19320c0773dbd8aef83d32a40d02a2a2b92859fe Author: Jens Axboe <axboe@xxxxxxxxx> Date: Mon Dec 9 20:58:56 2019 -0700 net: make socket read/write_iter() honor IOCB_NOWAIT [ 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: netdev@xxxxxxxxxxxxxxx Acked-by: David Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/socket.c b/net/socket.c index d7a106028f0e..ca8de9e1582d 100644 --- a/net/socket.c +++ b/net/socket.c @@ -955,7 +955,7 @@ 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) @@ -980,7 +980,7 @@ 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)