rxrpc: Allow the app to store private data on peer structs

Provide a way for the application (e.g. the afs filesystem) to store
private data on the rxrpc_peer structs for later retrieval via the call
object.

This will allow afs to store a pointer to the afs_server object on the
rxrpc_peer struct, thereby obviating the need for afs to keep lookup tables
by which it can associate an incoming call with server that transmitted it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20250224234154.2014840-13-dhowells@redhat.com/
Link: https://lore.kernel.org/r/20250310094206.801057-9-dhowells@redhat.com/

diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
index 0754c463224a434da23de5d4b0889563fa9fa33b..cf793d18e5df510be2929727e43fb496783ca92c 100644 (file)
--- a/include/net/af_rxrpc.h
+++ b/include/net/af_rxrpc.h
@@ -69,6 +69,8 @@ struct rxrpc_peer *rxrpc_kernel_get_peer(struct rxrpc_peer *peer);
 struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call);
 const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer);
 const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer);
+unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data);
+unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer);
 unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *);
 int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,
                               rxrpc_user_attach_call_t, unsigned long, gfp_t,

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index a64a0cab1bf7f92a89bbc4fd14987ad335b1ff9f..3cc3af15086ff1b2dda5a333299abccbb8ef1b3e 100644 (file)
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -344,6 +344,7 @@ struct rxrpc_peer {
        struct hlist_head       error_targets;  /* targets for net error distribution */
        struct rb_root          service_conns;  /* Service connections */
        struct list_head        keepalive_link; /* Link in net->peer_keepalive[] */
+       unsigned long           app_data;       /* Application data (e.g. afs_server) */
        time64_t                last_tx_at;     /* Last time packet sent here */
        seqlock_t               service_conn_lock;
        spinlock_t              lock;           /* access lock */

diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index 56e09d161a97f538964f1a0c0003f2b3a1bc4c98..a0c0e4d590f5c4a5ecb58491770aa7215eb7d6cb 100644 (file)
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -520,3 +520,29 @@ const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer)
                (peer ? &peer->srx.transport : &rxrpc_null_addr.transport);
 }
 EXPORT_SYMBOL(rxrpc_kernel_remote_addr);
+
+/**
+ * rxrpc_kernel_set_peer_data - Set app-specific data on a peer.
+ * @peer: The peer to alter
+ * @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.
+ */
+unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data)
+{
+       return xchg(&peer->app_data, app_data);
+}
+EXPORT_SYMBOL(rxrpc_kernel_set_peer_data);
+
+/**
+ * rxrpc_kernel_get_peer_data - Get app-specific data from a peer.
+ * @peer: The peer to query
+ *
+ * Retrieve the app-specific data from a peer.
+ */
+unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer)
+{
+       return peer->app_data;
+}
+EXPORT_SYMBOL(rxrpc_kernel_get_peer_data);