[PATCH net v3 06/14] rxrpc: Fix generation of notifications after call completion
From: David Howells <dhowells@redhat.com>
Date: 2026-07-13 08:11:05
Also in:
lkml
Subsystem:
networking [general], rxrpc sockets (af_rxrpc), the rest, tracing · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Howells, Marc Dionne, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
AF_RXRPC may generate a notification to the application after a call has
completed because it generates one notification when
rxrpc_input_split_jumbo() queues the final packet and completes the call
and then generates another when rxrpc_input_split_jumbo() does the
aggregated data receive notification at the end of the function.
This might cause the AFS filesystem to malfunction because it tries to
queue the afs_call for processing an extra time. Most of the time this
happens quickly enough that the second queue_work skips, but sometimes this
means that the call work may happen a second time with implications for
afs_call lifetime management.
Fix this by:
(1) Create a lighter version of rxrpc_notify_socket() that's just used to
requeue a call for rxrpc_recvmsg() without creating another
notification.
(2) Move rxrpc_notify_socket() to call_state.c and rename it to
__rxrpc_notify_socket().
(3) Create a wrapper called rxrpc_notify_socket() that skips the
notification if a call is completed.
(4) Make rxrpc_set_call_completion() call __rxrpc_notify_socket() to avoid
the skip-if-completed check.
Fixes: 2d1faf7a0ca3 ("rxrpc: Simplify skbuff accounting in receive path")
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@kernel.org
---
include/trace/events/rxrpc.h | 1 +
net/rxrpc/call_state.c | 57 +++++++++++++++++++++++++++++++++++-
net/rxrpc/recvmsg.c | 42 +++++++++-----------------
3 files changed, 71 insertions(+), 29 deletions(-)
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 8f3e3967885a..d7c7b04d69fc 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h@@ -343,6 +343,7 @@ EM(rxrpc_call_see_distribute_error, "SEE dist-err") \ EM(rxrpc_call_see_input, "SEE input ") \ EM(rxrpc_call_see_notify_released, "SEE nfy-rlsd") \ + EM(rxrpc_call_see_notify_skipped, "SEE nfy-skip") \ EM(rxrpc_call_see_recvmsg, "SEE recvmsg ") \ EM(rxrpc_call_see_recvmsg_requeue, "SEE recv-rqu") \ EM(rxrpc_call_see_recvmsg_requeue_first, "SEE recv-rqF") \
diff --git a/net/rxrpc/call_state.c b/net/rxrpc/call_state.c
index 6afb54373ebb..6e402312e145 100644
--- a/net/rxrpc/call_state.c
+++ b/net/rxrpc/call_state.c@@ -7,6 +7,61 @@ #include "ar-internal.h" +/* + * Post a call for attention by the socket or kernel service. Further + * notifications are suppressed by putting recvmsg_link on a dummy queue. + */ +static void __rxrpc_notify_socket(struct rxrpc_call *call) +{ + struct rxrpc_sock *rx; + struct sock *sk; + + if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) { + rxrpc_see_call(call, rxrpc_call_see_notify_released); + return; + } + + rcu_read_lock(); + + rx = rcu_dereference(call->socket); + sk = &rx->sk; + if (rx && sk->sk_state < RXRPC_CLOSE) { + if (call->notify_rx) { + spin_lock_irq(&call->notify_lock); + call->notify_rx(sk, call, call->user_call_ID); + spin_unlock_irq(&call->notify_lock); + } else { + spin_lock_irq(&rx->recvmsg_lock); + if (list_empty(&call->recvmsg_link)) { + rxrpc_get_call(call, rxrpc_call_get_notify_socket); + list_add_tail(&call->recvmsg_link, &rx->recvmsg_q); + } + spin_unlock_irq(&rx->recvmsg_lock); + + if (!sock_flag(sk, SOCK_DEAD)) { + _debug("call %ps", sk->sk_data_ready); + sk->sk_data_ready(sk); + } + } + } + + rcu_read_unlock(); +} + +/* + * Post a call for attention by the socket or kernel service. Further + * notifications are suppressed by putting recvmsg_link on a dummy queue. + */ +void rxrpc_notify_socket(struct rxrpc_call *call) +{ + if (rxrpc_call_is_complete(call)) { + rxrpc_see_call(call, rxrpc_call_see_notify_skipped); + return; + } + + __rxrpc_notify_socket(call); +} + /* * Transition a call to the complete state. */
@@ -25,7 +80,7 @@ bool rxrpc_set_call_completion(struct rxrpc_call *call, rxrpc_set_call_state(call, RXRPC_CALL_COMPLETE); trace_rxrpc_call_complete(call); wake_up(&call->waitq); - rxrpc_notify_socket(call); + __rxrpc_notify_socket(call); return true; }
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index efcba4b2e74f..28b2148b5693 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c@@ -17,13 +17,12 @@ #include "ar-internal.h" /* - * Post a call for attention by the socket or kernel service. Further - * notifications are suppressed by putting recvmsg_link on a dummy queue. + * Requeue a call for recvmsg() to pick up. */ -void rxrpc_notify_socket(struct rxrpc_call *call) +static void rxrpc_requeue_call(struct socket *sock, struct rxrpc_call *call) { - struct rxrpc_sock *rx; - struct sock *sk; + struct rxrpc_sock *rx = rxrpc_sk(sock->sk); + struct sock *sk = &rx->sk; _enter("%d", call->debug_id);
@@ -32,31 +31,18 @@ void rxrpc_notify_socket(struct rxrpc_call *call) return; } - rcu_read_lock(); - - rx = rcu_dereference(call->socket); - sk = &rx->sk; - if (rx && sk->sk_state < RXRPC_CLOSE) { - if (call->notify_rx) { - spin_lock_irq(&call->notify_lock); - call->notify_rx(sk, call, call->user_call_ID); - spin_unlock_irq(&call->notify_lock); - } else { - spin_lock_irq(&rx->recvmsg_lock); - if (list_empty(&call->recvmsg_link)) { - rxrpc_get_call(call, rxrpc_call_get_notify_socket); - list_add_tail(&call->recvmsg_link, &rx->recvmsg_q); - } - spin_unlock_irq(&rx->recvmsg_lock); + spin_lock_irq(&rx->recvmsg_lock); + if (list_empty(&call->recvmsg_link)) { + rxrpc_get_call(call, rxrpc_call_get_notify_socket); + list_add_tail(&call->recvmsg_link, &rx->recvmsg_q); + } + spin_unlock_irq(&rx->recvmsg_lock); - if (!sock_flag(sk, SOCK_DEAD)) { - _debug("call %ps", sk->sk_data_ready); - sk->sk_data_ready(sk); - } - } + if (!sock_flag(sk, SOCK_DEAD)) { + _debug("call %ps", sk->sk_data_ready); + sk->sk_data_ready(sk); } - rcu_read_unlock(); _leave(""); }
@@ -561,7 +547,7 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, if (!(flags & MSG_PEEK) && !skb_queue_empty(&call->recvmsg_queue)) - rxrpc_notify_socket(call); + rxrpc_requeue_call(sock, call); goto not_yet_complete; call_failed: