[PATCH 5.10 24/98] io_uring: support MSG_WAITALL for IORING_OP_SEND(MSG)

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Jens Axboe <axboe@xxxxxxxxx>

commit 4c3c09439c08b03d9503df0ca4c7619c5842892e upstream.

Like commit 7ba89d2af17a for recv/recvmsg, support MSG_WAITALL for the
send side. If this flag is set and we do a short send, retry for a
stream of seqpacket socket.

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 io_uring/io_uring.c | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 7f9fb0cb9230..75d833269751 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -4617,6 +4617,13 @@ static int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags)
 }
 
 #if defined(CONFIG_NET)
+static bool io_net_retry(struct socket *sock, int flags)
+{
+	if (!(flags & MSG_WAITALL))
+		return false;
+	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
+}
+
 static int io_setup_async_msg(struct io_kiocb *req,
 			      struct io_async_msghdr *kmsg)
 {
@@ -4680,12 +4687,14 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (req->ctx->compat)
 		sr->msg_flags |= MSG_CMSG_COMPAT;
 #endif
+	sr->done_io = 0;
 	return 0;
 }
 
 static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_async_msghdr iomsg, *kmsg;
+	struct io_sr_msg *sr = &req->sr_msg;
 	struct socket *sock;
 	unsigned flags;
 	int min_ret = 0;
@@ -4716,12 +4725,21 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 			return io_setup_async_msg(req, kmsg);
 		if (ret == -ERESTARTSYS)
 			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return io_setup_async_msg(req, kmsg);
+		}
 		req_set_fail(req);
 	}
 	/* fast path, check for non-NULL to avoid function call */
 	if (kmsg->free_iov)
 		kfree(kmsg->free_iov);
 	req->flags &= ~REQ_F_NEED_CLEANUP;
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
 	__io_req_complete(req, issue_flags, ret, 0);
 	return 0;
 }
@@ -4762,8 +4780,19 @@ static int io_send(struct io_kiocb *req, unsigned int issue_flags)
 			return -EAGAIN;
 		if (ret == -ERESTARTSYS)
 			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->len -= ret;
+			sr->buf += ret;
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return -EAGAIN;
+		}
 		req_set_fail(req);
 	}
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
 	__io_req_complete(req, issue_flags, ret, 0);
 	return 0;
 }
@@ -4911,13 +4940,6 @@ static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return 0;
 }
 
-static bool io_net_retry(struct socket *sock, int flags)
-{
-	if (!(flags & MSG_WAITALL))
-		return false;
-	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
-}
-
 static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_async_msghdr iomsg, *kmsg;
-- 
2.39.0