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-rw-r--r--net/netlink/af_netlink.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 50889be1517d..173817a5dfad 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -674,12 +674,19 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock,
mask = datagram_poll(file, sock, wait);
- spin_lock_bh(&sk->sk_receive_queue.lock);
- if (nlk->rx_ring.pg_vec) {
- if (netlink_has_valid_frame(&nlk->rx_ring))
- mask |= POLLIN | POLLRDNORM;
+ /* We could already have received frames in the normal receive
+ * queue, that will show up as NL_MMAP_STATUS_COPY in the ring,
+ * so if mask contains pollin/etc already, there's no point
+ * walking the ring.
+ */
+ if ((mask & (POLLIN | POLLRDNORM)) != (POLLIN | POLLRDNORM)) {
+ spin_lock_bh(&sk->sk_receive_queue.lock);
+ if (nlk->rx_ring.pg_vec) {
+ if (netlink_has_valid_frame(&nlk->rx_ring))
+ mask |= POLLIN | POLLRDNORM;
+ }
+ spin_unlock_bh(&sk->sk_receive_queue.lock);
}
- spin_unlock_bh(&sk->sk_receive_queue.lock);
spin_lock_bh(&sk->sk_write_queue.lock);
if (nlk->tx_ring.pg_vec) {