[PATCH net v12 09/15] rxrpc: Fix return in rxrpc_recvmsg_data() for service calls

[David Howells]

When rxrpc_recvmsg_data() gets called on a service call that has received
all of the request, RXRPC_CALL_RECVMSG_READ_ALL has been set, and this
causes rxrpc_recvmsg_data() to jump straight out, indicating the end of the
call (ie. rxrpc_kernel_recv_data() returns 1) without waiting for the call
to be processed or the reply to be transmitted.

rxperf_deliver_to_call() also has to be altered to call
rxrpc_kernel_recv_data() to collect the final ACK on a service call as does
afs_deliver_to_call().

Fixes: d001648ec7cf ("rxrpc: Don't expose skbs to in-kernel users [ver #2]")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260914151340.3227501-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: Jeffrey Altman <jaltman@xxxxxxxxxxxx>
cc: Eric Dumazet <edumazet@xxxxxxxxxx>
cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
cc: Jakub Kicinski <kuba@xxxxxxxxxx>
cc: Paolo Abeni <pabeni@xxxxxxxxxx>
cc: Simon Horman <horms@xxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
cc: stable@xxxxxxxxxxxxxxx
---
 Documentation/networking/rxrpc.rst | 13 +++++++++----
 fs/afs/rxrpc.c                     |  4 ++--
 net/rxrpc/recvmsg.c                | 13 ++++++++++---
 net/rxrpc/rxperf.c                 | 16 ++++++++++++++--
 4 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/Documentation/networking/rxrpc.rst b/Documentation/networking/rxrpc.rst
index 9239f7bd8885..eca055a536aa 100644
--- a/Documentation/networking/rxrpc.rst
+++ b/Documentation/networking/rxrpc.rst
@@ -909,10 +909,15 @@ The kernel interface functions are as follows:
       want_more should be true if further data will be required after this is
       satisfied and false if this is the last item of the receive phase.
 
-      There are three normal returns: 0 if the buffer was filled and want_more
-      was true; 1 if the buffer was filled, the last DATA packet has been
-      emptied and want_more was false; and -EAGAIN if the function needs to be
-      called again.
+      For client calls, there are three normal returns: 0 if the buffer was
+      filled and want_more was true; 1 if the buffer was filled, the last DATA
+      packet has been emptied and want_more was false; and -EAGAIN if the
+      function needs to be called again.
+
+      For service calls, there are four normal returns: 0 and -EAGAIN are the
+      same as for client calls; 2 indicates that the last DATA packet of the
+      request has been received, want_more was false and the call is still in
+      progress; and 1 indicates that the call is now successfully complete.
 
       If the last DATA packet is processed but the buffer contains less than
       the amount requested, EBADMSG is returned.  If want_more wasn't set, but
diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 64dd32df8a34..768b26820dea 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -541,7 +541,7 @@ void afs_deliver_to_call(struct afs_call *call)
 						     &call->service_id);
 			trace_afs_receive_data(call, &call->def_iter, false, ret);
 
-			if (ret == -EINPROGRESS || ret == -EAGAIN)
+			if (ret == -EAGAIN || ret == 2)
 				return;
 			if (ret < 0 || ret == 1) {
 				if (ret == 1)
@@ -934,7 +934,7 @@ int afs_extract_data(struct afs_call *call, bool want_more)
 		return ret;
 
 	state = READ_ONCE(call->state);
-	if (ret == 1) {
+	if (ret == 1 || ret == 2) {
 		switch (state) {
 		case AFS_CALL_CL_AWAIT_REPLY:
 			afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 56fa324d0962..0c960f13b5fc 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -638,9 +638,11 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
  * Note that we may return %-EAGAIN to drain empty packets at the end
  * of the data, even if we've already copied over the requested data.
  *
- * Return: %0 if got what was asked for and there's more available, %1
- * if we got what was asked for and we're at the end of the data and
- * %-EAGAIN if we need more data.
+ * Return: %0 if got what was asked for and there's more available, %1 if we
+ * got what was asked for and we're at the end of the call, %2 if a service
+ * call received all of the request but is still in progress and %-EAGAIN if we
+ * need more data.  A variety of other errors can be returned if the call
+ * completed with failure.
  */
 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 			   struct iov_iter *iter, size_t *_len,
@@ -679,6 +681,11 @@ int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 
 read_phase_complete:
 	ret = 1;
+	if (rxrpc_is_service_call(call)) {
+		if (rxrpc_call_is_complete(call))
+			goto call_failed;
+		ret = 2;
+	}
 out:
 	if (_service)
 		*_service = call->dest_srx.srx_service;
diff --git a/net/rxrpc/rxperf.c b/net/rxrpc/rxperf.c
index 823eedc5d16f..0bc3de061b93 100644
--- a/net/rxrpc/rxperf.c
+++ b/net/rxrpc/rxperf.c
@@ -293,8 +293,20 @@ static void rxperf_deliver_to_call(struct work_struct *work)
 	       state == RXPERF_CALL_SV_AWAIT_ACK
 	       ) {
 		if (state == RXPERF_CALL_SV_AWAIT_ACK) {
-			if (!rxrpc_kernel_check_life(rxperf_socket, call->rxcall))
+			size_t len = 0;
+			iov_iter_kvec(&call->iter, ITER_DEST, NULL, 0, 0);
+			ret = rxrpc_kernel_recv_data(rxperf_socket,
+						     call->rxcall, &call->iter,
+						     &len, false, &remote_abort,
+						     &call->service_id);
+
+			if (ret == -EAGAIN || ret == 2)
+				return;
+			if (ret < 0 || ret == 1) {
+				if (ret == 1)
+					ret = 0;
 				goto call_complete;
+			}
 			return;
 		}
 
@@ -369,7 +381,7 @@ static int rxperf_extract_data(struct rxperf_call *call, bool want_more)
 	if (ret == 0 || ret == -EAGAIN)
 		return ret;
 
-	if (ret == 1) {
+	if (ret == 1 || ret == 2) {
 		switch (call->state) {
 		case RXPERF_CALL_SV_AWAIT_REQUEST:
 			rxperf_set_call_state(call, RXPERF_CALL_SV_REPLYING);