From: "Linus Lüssing" <linus.luessing@c0d3.blue>
To: b.a.t.m.a.n@lists.open-mesh.org
Subject: [B.A.T.M.A.N.] [PATCHv3 maint 4/5] batman-adv: Make MCAST capability changes atomic
Date: Tue, 16 Jun 2015 15:17:22 +0200 [thread overview]
Message-ID: <1434460643-3681-5-git-send-email-linus.luessing@c0d3.blue> (raw)
In-Reply-To: <1434460643-3681-1-git-send-email-linus.luessing@c0d3.blue>
Bitwise OR/AND assignments in C aren't guaranteed to be atomic. One
OGM handler might undo the set/clear of a specific bit from another
handler run in between.
Fix this by using the atomic set_bit()/clear_bit() functions.
Fixes: 77ec494490d6 ("batman-adv: Announce new capability via multicast TVLV")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
multicast.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/multicast.c b/multicast.c
index 09f2838..00612bf 100644
--- a/multicast.c
+++ b/multicast.c
@@ -684,7 +684,7 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST)) {
if (orig_initialized)
atomic_dec(&bat_priv->mcast.num_disabled);
- orig->capabilities |= BATADV_ORIG_CAPA_HAS_MCAST;
+ set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);
/* If mcast support is being switched off or if this is an initial
* OGM without mcast support then increase the disabled mcast
* node counter.
@@ -693,10 +693,10 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST ||
!orig_initialized)) {
atomic_inc(&bat_priv->mcast.num_disabled);
- orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_MCAST;
+ clear_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);
}
- orig->capa_initialized |= BATADV_ORIG_CAPA_HAS_MCAST;
+ set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized);
if (orig_mcast_enabled && tvlv_value &&
(tvlv_value_len >= sizeof(mcast_flags)))
--
1.7.10.4
next prev parent reply other threads:[~2015-06-16 13:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-16 13:17 [B.A.T.M.A.N.] [PATCHv3 maint 0/5] Fixes for parallel OGM processing Linus Lüssing
2015-06-16 13:17 ` [B.A.T.M.A.N.] [PATCHv3 maint 1/5] batman-adv: Make DAT capability changes atomic Linus Lüssing
2015-06-16 13:17 ` [B.A.T.M.A.N.] [PATCHv3 maint 2/5] batman-adv: Make NC " Linus Lüssing
2015-06-16 13:17 ` [B.A.T.M.A.N.] [PATCHv3 maint 3/5] batman-adv: Make TT " Linus Lüssing
2015-06-16 13:17 ` Linus Lüssing [this message]
2015-06-16 13:17 ` [B.A.T.M.A.N.] [PATCHv3 maint 5/5] batman-adv: Fix potential synchronization issues in mcast tvlv handler Linus Lüssing
2015-06-16 14:12 ` Marek Lindner
2015-06-16 14:38 ` Marek Lindner
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