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authorWillem de Bruijn <willemb@google.com>2015-05-14 22:25:02 +0300
committerDavid S. Miller <davem@davemloft.net>2015-05-15 00:40:54 +0300
commit54d7c01d3ed699cfc213115eaecfe1175cfaff8f (patch)
treea3549400cc77b55a19ea400a3f6623f461739139 /net/packet
parent4ffd3c730e7ba2eb53a427f1a2bba2eec5f2d97b (diff)
downloadlinux-54d7c01d3ed699cfc213115eaecfe1175cfaff8f.tar.xz
packet: fix warnings in rollover lock contention
Avoid two xchg calls whose return values were unused, causing a warning on some architectures. The relevant variable is a hint and read without mutual exclusion. This fix makes all writers hold the receive_queue lock. Suggested-by: David S. Miller <davem@davemloft.net> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c15
1 files changed, 5 insertions, 10 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 31d58565726c..c30d14781576 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1301,17 +1301,12 @@ static int packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
int ret;
bool has_room;
- if (po->prot_hook.func == tpacket_rcv) {
- spin_lock(&po->sk.sk_receive_queue.lock);
- ret = __packet_rcv_has_room(po, skb);
- spin_unlock(&po->sk.sk_receive_queue.lock);
- } else {
- ret = __packet_rcv_has_room(po, skb);
- }
-
+ spin_lock_bh(&po->sk.sk_receive_queue.lock);
+ ret = __packet_rcv_has_room(po, skb);
has_room = ret == ROOM_NORMAL;
if (po->pressure == has_room)
- xchg(&po->pressure, !has_room);
+ po->pressure = !has_room;
+ spin_unlock_bh(&po->sk.sk_receive_queue.lock);
return ret;
}
@@ -3814,7 +3809,7 @@ static unsigned int packet_poll(struct file *file, struct socket *sock,
mask |= POLLIN | POLLRDNORM;
}
if (po->pressure && __packet_rcv_has_room(po, NULL) == ROOM_NORMAL)
- xchg(&po->pressure, 0);
+ po->pressure = 0;
spin_unlock_bh(&sk->sk_receive_queue.lock);
spin_lock_bh(&sk->sk_write_queue.lock);
if (po->tx_ring.pg_vec) {