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. Also remove the comment on rxrpc_notify_socket() that said it added the call to a dummy queue to prevent further notification. Fixes: 2d1faf7a0ca3 ("rxrpc: Simplify skbuff accounting in receive path") Signed-off-by: David Howells cc: Marc Dionne cc: Eric Dumazet cc: "David S. Miller" cc: Jakub Kicinski cc: Paolo Abeni cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org --- include/trace/events/rxrpc.h | 1 + net/rxrpc/ar-internal.h | 2 +- net/rxrpc/call_state.c | 56 +++++++++++++++++++++++++++++++++++- net/rxrpc/recvmsg.c | 43 +++++++++------------------ 4 files changed, 71 insertions(+), 31 deletions(-) diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index a5c92592d8f9..52f8718cf725 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/ar-internal.h b/net/rxrpc/ar-internal.h index a6f830c1621f..cb36a709f540 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1110,6 +1110,7 @@ static inline bool rxrpc_is_client_call(const struct rxrpc_call *call) /* * call_state.c */ +void rxrpc_notify_socket(struct rxrpc_call *call); bool rxrpc_set_call_completion(struct rxrpc_call *call, enum rxrpc_call_completion compl, u32 abort_code, @@ -1442,7 +1443,6 @@ extern const struct seq_operations rxrpc_local_seq_ops; /* * recvmsg.c */ -void rxrpc_notify_socket(struct rxrpc_call *); int rxrpc_recvmsg(struct socket *, struct msghdr *, size_t, int); /* diff --git a/net/rxrpc/call_state.c b/net/rxrpc/call_state.c index 6afb54373ebb..364810c65276 100644 --- a/net/rxrpc/call_state.c +++ b/net/rxrpc/call_state.c @@ -7,6 +7,60 @@ #include "ar-internal.h" +/* + * Post a call for attention by the socket or kernel service. + */ +static void __rxrpc_notify_socket(struct rxrpc_call *call) +{ + struct rxrpc_sock *rx; + struct sock *sk; + unsigned long flags; + + 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_irqsave(&call->notify_lock, flags); + call->notify_rx(sk, call, call->user_call_ID); + spin_unlock_irqrestore(&call->notify_lock, flags); + } else { + spin_lock_irqsave(&rx->recvmsg_lock, flags); + 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_irqrestore(&rx->recvmsg_lock, flags); + + 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. + */ +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 +79,7 @@ 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 56fa324d0962..28b2148b5693 100644 --- a/net/rxrpc/recvmsg.c +++ b/net/rxrpc/recvmsg.c @@ -17,14 +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; - unsigned long flags; + struct rxrpc_sock *rx = rxrpc_sk(sock->sk); + struct sock *sk = &rx->sk; _enter("%d", call->debug_id); @@ -33,31 +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_irqsave(&call->notify_lock, flags); - call->notify_rx(sk, call, call->user_call_ID); - spin_unlock_irqrestore(&call->notify_lock, flags); - } else { - spin_lock_irqsave(&rx->recvmsg_lock, flags); - 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_irqrestore(&rx->recvmsg_lock, flags); + 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(""); } @@ -562,7 +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: