[PATCH 4/4] io_uring: wire up IOSQE2_POLL_FIRST for send/sendmsg and recv/recvmsg

[Jens Axboe <axboe@kernel.dk>]

If REQ_F_POLL_FIRST is set and we haven't polled for this request before,
go straight to checking poll status before attempting a data transfer.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index eb5f77bde98d..3ae18604ed59 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5315,6 +5315,9 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 		kmsg = &iomsg;
 	}
 
+	if ((req->flags & (REQ_F_POLLED | REQ_F_POLL_FIRST)) == REQ_F_POLL_FIRST)
+		return io_setup_async_msg(req, kmsg);
+
 	flags = req->sr_msg.msg_flags;
 	if (issue_flags & IO_URING_F_NONBLOCK)
 		flags |= MSG_DONTWAIT;
@@ -5357,6 +5360,9 @@ static int io_send(struct io_kiocb *req, unsigned int issue_flags)
 	int min_ret = 0;
 	int ret;
 
+	if ((req->flags & (REQ_F_POLLED | REQ_F_POLL_FIRST)) == REQ_F_POLL_FIRST)
+		return -EAGAIN;
+
 	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
 		return -ENOTSOCK;
@@ -5547,6 +5553,9 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
 		kmsg = &iomsg;
 	}
 
+	if ((req->flags & (REQ_F_POLLED | REQ_F_POLL_FIRST)) == REQ_F_POLL_FIRST)
+		return io_setup_async_msg(req, kmsg);
+
 	if (req->flags & REQ_F_BUFFER_SELECT) {
 		kbuf = io_recv_buffer_select(req, issue_flags);
 		if (IS_ERR(kbuf))
@@ -5604,6 +5613,9 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
 	int ret, min_ret = 0;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 
+	if ((req->flags & (REQ_F_POLLED | REQ_F_POLL_FIRST)) == REQ_F_POLL_FIRST)
+		return -EAGAIN;
+
 	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
 		return -ENOTSOCK;
-- 
2.35.1