rxrpc: kdoc: Update function descriptions and add link from rxrpc.rst

Update the kerneldoc function descriptions to add "Return:" sections for
AF_RXRPC exported functions that have return values to stop the kdoc
builder from throwing warnings.

Also add links from the rxrpc.rst API doc to add a function API reference
at the end.  (Note that the API doc really needs updating, but that's
beyond this patchset).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-2-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/rxrpc.rst

@@ -1172,3 +1172,14 @@ adjusted through sysctls in /proc/net/rxrpc/:
      header plus exactly 1412 bytes of data.  The terminal packet must contain
      a four byte header plus any amount of data.  In any event, a jumbo packet
      may not exceed rxrpc_rx_mtu in size.
+
+
+API Function Reference
+======================
+
+.. kernel-doc:: net/rxrpc/af_rxrpc.c
+.. kernel-doc:: net/rxrpc/key.c
+.. kernel-doc:: net/rxrpc/peer_object.c
+.. kernel-doc:: net/rxrpc/recvmsg.c
+.. kernel-doc:: net/rxrpc/sendmsg.c
+.. kernel-doc:: net/rxrpc/server_key.c

net/rxrpc/af_rxrpc.c

@@ -265,7 +265,10 @@ static int rxrpc_listen(struct socket *sock, int backlog)
  * @gfp: Allocation flags
  *
  * Lookup or create a remote transport endpoint record for the specified
- * address and return it with a ref held.
+ * address.
+ *
+ * Return: The peer record found with a reference, %NULL if no record is found
+ * or a negative error code if the address is invalid or unsupported.
  */
 struct rxrpc_peer *rxrpc_kernel_lookup_peer(struct socket *sock,
 					    struct sockaddr_rxrpc *srx, gfp_t gfp)
@@ -283,9 +286,11 @@ EXPORT_SYMBOL(rxrpc_kernel_lookup_peer);
 
 /**
  * rxrpc_kernel_get_peer - Get a reference on a peer
- * @peer: The peer to get a reference on.
+ * @peer: The peer to get a reference on (may be NULL).
  *
- * Get a record for the remote peer in a call.
+ * Get a reference for a remote peer record (if not NULL).
+ *
+ * Return: The @peer argument.
  */
 struct rxrpc_peer *rxrpc_kernel_get_peer(struct rxrpc_peer *peer)
 {
@@ -296,6 +301,8 @@ EXPORT_SYMBOL(rxrpc_kernel_get_peer);
 /**
  * rxrpc_kernel_put_peer - Allow a kernel app to drop a peer reference
  * @peer: The peer to drop a ref on
+ *
+ * Drop a reference on a peer record.
  */
 void rxrpc_kernel_put_peer(struct rxrpc_peer *peer)
 {
@@ -320,10 +327,12 @@ EXPORT_SYMBOL(rxrpc_kernel_put_peer);
  *
  * Allow a kernel service to begin a call on the nominated socket.  This just
  * sets up all the internal tracking structures and allocates connection and
- * call IDs as appropriate.  The call to be used is returned.
+ * call IDs as appropriate.
  *
  * The default socket destination address and security may be overridden by
  * supplying @srx and @key.
+ *
+ * Return: The new call or an error code.
  */
 struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
 					   struct rxrpc_peer *peer,
@@ -437,6 +446,8 @@ EXPORT_SYMBOL(rxrpc_kernel_put_call);
  *
  * Allow a kernel service to find out whether a call is still alive - whether
  * it has completed successfully and all received data has been consumed.
+ *
+ * Return: %true if the call is still ongoing and %false if it has completed.
  */
 bool rxrpc_kernel_check_life(const struct socket *sock,
 			     const struct rxrpc_call *call)
@@ -456,6 +467,8 @@ EXPORT_SYMBOL(rxrpc_kernel_check_life);
  *
  * Allow a kernel service to retrieve the epoch value from a service call to
  * see if the client at the other end rebooted.
+ *
+ * Return: The epoch of the call's connection.
  */
 u32 rxrpc_kernel_get_epoch(struct socket *sock, struct rxrpc_call *call)
 {

net/rxrpc/key.c

@@ -531,6 +531,8 @@ EXPORT_SYMBOL(rxrpc_get_server_data_key);
  *
  * Generate a null RxRPC key that can be used to indicate anonymous security is
  * required for a particular domain.
+ *
+ * Return: The new key or a negative error code.
  */
 struct key *rxrpc_get_null_key(const char *keyname)
 {

net/rxrpc/peer_object.c

@@ -475,6 +475,8 @@ void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
  * @call: The call to query
  *
  * Get a record for the remote peer in a call.
+ *
+ * Return: The call's peer record.
  */
 struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call)
 {
@@ -486,7 +488,9 @@ EXPORT_SYMBOL(rxrpc_kernel_get_call_peer);
  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
  * @peer: The peer to query
  *
- * Get the call's peer smoothed RTT in uS or UINT_MAX if we have no samples.
+ * Get the call's peer smoothed RTT.
+ *
+ * Return: The RTT in uS or %UINT_MAX if we have no samples.
  */
 unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer)
 {
@@ -499,7 +503,10 @@ EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
  * @peer: The peer to query
  *
  * Get a pointer to the address from a peer record.  The caller is responsible
- * for making sure that the address is not deallocated.
+ * for making sure that the address is not deallocated.  A fake address will be
+ * substituted if %peer in NULL.
+ *
+ * Return: The rxrpc address record or a fake record.
  */
 const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer)
 {
@@ -512,7 +519,10 @@ EXPORT_SYMBOL(rxrpc_kernel_remote_srx);
  * @peer: The peer to query
  *
  * Get a pointer to the transport address from a peer record.  The caller is
- * responsible for making sure that the address is not deallocated.
+ * responsible for making sure that the address is not deallocated.  A fake
+ * address will be substituted if %peer in NULL.
+ *
+ * Return: The transport address record or a fake record.
  */
 const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer)
 {
@@ -527,7 +537,9 @@ EXPORT_SYMBOL(rxrpc_kernel_remote_addr);
  * @app_data: The data to set
  *
  * Set the app-specific data on a peer.  AF_RXRPC makes no effort to retain
- * anything the data might refer to.  The previous app_data is returned.
+ * anything the data might refer to.
+ *
+ * Return: The previous app_data.
  */
 unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data)
 {
@@ -540,6 +552,8 @@ EXPORT_SYMBOL(rxrpc_kernel_set_peer_data);
  * @peer: The peer to query
  *
  * Retrieve the app-specific data from a peer.
+ *
+ * Return: The peer's app data.
  */
 unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer)
 {

net/rxrpc/recvmsg.c

@@ -477,14 +477,14 @@ wait_error:
  * @_service: Where to store the actual service ID (may be upgraded)
  *
  * Allow a kernel service to receive data and pick up information about the
- * state of a call.  Returns 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.
+ * state of a call.  Note that *@_abort should also be initialised to %0.
  *
- * 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.
+ * 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.
  *
- * *_abort should also be initialised to 0.
+ * 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.
  */
 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 			   struct iov_iter *iter, size_t *_len,

net/rxrpc/sendmsg.c

@@ -794,6 +794,8 @@ error_release_sock:
  * appropriate to sending data.  No control data should be supplied in @msg,
  * nor should an address be supplied.  MSG_MORE should be flagged if there's
  * more data to come, otherwise this data will end the transmission phase.
+ *
+ * Return: %0 if successful and a negative error code otherwise.
  */
 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 			   struct msghdr *msg, size_t len,
@@ -829,8 +831,9 @@ EXPORT_SYMBOL(rxrpc_kernel_send_data);
  * @error: Local error value
  * @why: Indication as to why.
  *
- * Allow a kernel service to abort a call, if it's still in an abortable state
- * and return true if the call was aborted, false if it was already complete.
+ * Allow a kernel service to abort a call if it's still in an abortable state.
+ *
+ * Return: %true if the call was aborted, %false if it was already complete.
  */
 bool rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
 			     u32 abort_code, int error, enum rxrpc_abort_reason why)

net/rxrpc/server_key.c

@@ -152,6 +152,8 @@ int rxrpc_server_keyring(struct rxrpc_sock *rx, sockptr_t optval, int optlen)
  *
  * Set the server security keyring on an rxrpc socket.  This is used to provide
  * the encryption keys for a kernel service.
+ *
+ * Return: %0 if successful and a negative error code otherwise.
  */
 int rxrpc_sock_set_security_keyring(struct sock *sk, struct key *keyring)
 {