summary | shortlog | log | commit | commitdiff | tree
raw | patch | inline | side by side (parent: 06f6b59)
raw | patch | inline | side by side (parent: 06f6b59)
author | Willem de Bruijn <willemb@google.com> | |
Wed, 17 Jun 2015 19:59:34 +0000 (15:59 -0400) | ||
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
Fri, 10 Jul 2015 17:37:56 +0000 (10:37 -0700) |
[ Upstream commit 468479e6043c84f5a65299cc07cb08a22a28c2b1 ]
PACKET_FANOUT_LB computes f->rr_cur such that it is modulo
f->num_members. It returns the old value unconditionally, but
f->num_members may have changed since the last store. Ensure
that the return value is always < num.
When modifying the logic, simplify it further by replacing the loop
with an unconditional atomic increment.
Fixes: dc99f600698d ("packet: Add fanout support.")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PACKET_FANOUT_LB computes f->rr_cur such that it is modulo
f->num_members. It returns the old value unconditionally, but
f->num_members may have changed since the last store. Ensure
that the return value is always < num.
When modifying the logic, simplify it further by replacing the loop
with an unconditional atomic increment.
Fixes: dc99f600698d ("packet: Add fanout support.")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/packet/af_packet.c | patch | blob | history |
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index f238530bd1b504b1a4e41259ccdc4a15b6a0e13f..84a60b82e235504b74c29b23253a5b7fae68dcff 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
sk_refcnt_debug_dec(sk);
}
-static int fanout_rr_next(struct packet_fanout *f, unsigned int num)
-{
- int x = atomic_read(&f->rr_cur) + 1;
-
- if (x >= num)
- x = 0;
-
- return x;
-}
-
static unsigned int fanout_demux_hash(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
struct sk_buff *skb,
unsigned int num)
{
- int cur, old;
+ unsigned int val = atomic_inc_return(&f->rr_cur);
- cur = atomic_read(&f->rr_cur);
- while ((old = atomic_cmpxchg(&f->rr_cur, cur,
- fanout_rr_next(f, num))) != cur)
- cur = old;
- return cur;
+ return val % num;
}
static unsigned int fanout_demux_cpu(struct packet_fanout *f,