[PATCH net v9 01/14] afs: Fix lack of loop around sendmsg() to rxrpc

[David Howells <dhowells@redhat.com>]

Fix the afs callers of sendmsg() to send data through an rxrpc socket to
call again if a short send occurs.

Note that this is also a prerequisite for changing the way rxrpc_send_data()
works to return a short send rather than an error if some data was buffered.

Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: stable@vger.kernel.org
---
 fs/afs/rxrpc.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index d82916657a3d..a80b043d36be 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -412,26 +412,32 @@ void afs_make_call(struct afs_call *call, gfp_t gfp)
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
 
-	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
-				     &msg, call->request_size,
-				     afs_notify_end_request_tx);
-	if (ret < 0)
-		goto error_do_abort;
+	do {
+		ret = rxrpc_kernel_send_data(call->net->socket, rxcall, &msg,
+					     msg_data_left(&msg),
+					     afs_notify_end_request_tx);
+		if (ret < 0)
+			goto error_do_abort;
+	} while (msg_data_left(&msg) > 0);
 
 	if (call->write_iter) {
 		msg.msg_iter = *call->write_iter;
 		msg.msg_flags &= ~MSG_MORE;
 		trace_afs_send_data(call, &msg);
 
-		ret = rxrpc_kernel_send_data(call->net->socket,
-					     call->rxcall, &msg,
-					     iov_iter_count(&msg.msg_iter),
-					     afs_notify_end_request_tx);
+		do {
+			ret = rxrpc_kernel_send_data(call->net->socket,
+						     call->rxcall, &msg,
+						     msg_data_left(&msg),
+						     afs_notify_end_request_tx);
+			if (ret < 0) {
+				trace_afs_sent_data(call, &msg, ret);
+				goto error_do_abort;
+			}
+		} while (msg_data_left(&msg) > 0);
 		*call->write_iter = msg.msg_iter;
 
-		trace_afs_sent_data(call, &msg, ret);
-		if (ret < 0)
-			goto error_do_abort;
+		trace_afs_sent_data(call, &msg, 0);
 	}
 
 	/* Note that at this point, we may have received the reply or an abort
@@ -912,8 +918,12 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
 
-	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
-				   afs_notify_end_reply_tx);
+	do {
+		n = rxrpc_kernel_send_data(net->socket, call->rxcall,
+					   &msg, msg_data_left(&msg),
+					   afs_notify_end_reply_tx);
+	} while (n >= 0 && msg_data_left(&msg) > 0);
+
 	if (n >= 0) {
 		/* Success */
 		_leave(" [replied]");