tcp: annotate sk->sk_wmem_queued lockless reads
For the sake of tcp_poll(), there are few places where we fetch
sk->sk_wmem_queued while this field can change from IRQ or other cpu.
We need to add READ_ONCE() annotations, and also make sure write
sides use corresponding WRITE_ONCE() to avoid store-tearing.
sk_wmem_queued_add() helper is added so that we can in
the future convert to ADD_ONCE() or equivalent if/when
available.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/em_meta.c b/net/sched/em_meta.c
index 4c9122f..3177dcb1 100644
--- a/net/sched/em_meta.c
+++ b/net/sched/em_meta.c
@@ -446,7 +446,7 @@ META_COLLECTOR(int_sk_wmem_queued)
*err = -1;
return;
}
- dst->value = sk->sk_wmem_queued;
+ dst->value = READ_ONCE(sk->sk_wmem_queued);
}
META_COLLECTOR(int_sk_fwd_alloc)
