[PATCH net-next] rxrpc: Disable IRQ, not BH, to take the lock for ->attend_link

[PATCH net-next] rxrpc: Disable IRQ, not BH, to take the lock for ->attend_link

[David Howells]

    
Use spin_lock_irq(), not spin_lock_bh() to take the lock when accessing the
->attend_link() to stop a delay in the I/O thread due to an interrupt being
taken in the app thread whilst that holds the lock and vice versa.

Fixes: a2ea9a907260 ("rxrpc: Use irq-disabling spinlocks between app and I/O thread")
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: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
---
 net/rxrpc/io_thread.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/rxrpc/io_thread.c b/net/rxrpc/io_thread.c
index 2925c7fc82cf..64f8d77b8731 100644
--- a/net/rxrpc/io_thread.c
+++ b/net/rxrpc/io_thread.c
@@ -508,9 +508,9 @@ int rxrpc_io_thread(void *data)
 		while ((conn = list_first_entry_or_null(&conn_attend_q,
 							struct rxrpc_connection,
 							attend_link))) {
-			spin_lock_bh(&local->lock);
+			spin_lock_irq(&local->lock);
 			list_del_init(&conn->attend_link);
-			spin_unlock_bh(&local->lock);
+			spin_unlock_irq(&local->lock);
 			rxrpc_input_conn_event(conn, NULL);
 			rxrpc_put_connection(conn, rxrpc_conn_put_poke);
 		}
@@ -527,9 +527,9 @@ int rxrpc_io_thread(void *data)
 		while ((call = list_first_entry_or_null(&call_attend_q,
 							struct rxrpc_call,
 							attend_link))) {
-			spin_lock_bh(&local->lock);
+			spin_lock_irq(&local->lock);
 			list_del_init(&call->attend_link);
-			spin_unlock_bh(&local->lock);
+			spin_unlock_irq(&local->lock);
 			trace_rxrpc_call_poked(call);
 			rxrpc_input_call_event(call);
 			rxrpc_put_call(call, rxrpc_call_put_poke);

Re: [PATCH net-next] rxrpc: Disable IRQ, not BH, to take the lock for ->attend_link

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 12 Dec 2024 20:58:15 +0000 you wrote:
> Use spin_lock_irq(), not spin_lock_bh() to take the lock when accessing the
> ->attend_link() to stop a delay in the I/O thread due to an interrupt being
> taken in the app thread whilst that holds the lock and vice versa.
> 
> Fixes: a2ea9a907260 ("rxrpc: Use irq-disabling spinlocks between app and I/O thread")
> 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: linux-afs@lists.infradead.org
> cc: netdev@vger.kernel.org
> 
> [...]

Here is the summary with links:
  - [net-next] rxrpc: Disable IRQ, not BH, to take the lock for ->attend_link
    https://git.kernel.org/netdev/net-next/c/d920270a6dbf

You are awesome, thank you!
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