From 9c936e3f4c4fad07abb6c082a89508b8f724c88f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Linus=20L=C3=BCssing?= Date: Tue, 16 Jun 2015 17:10:25 +0200 Subject: [PATCH] batman-adv: Make MCAST capability changes atomic MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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()/test_bit() functions. Fixes: 60432d756cf0 ("batman-adv: Announce new capability via multicast TVLV") Signed-off-by: Linus Lüssing Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- net/batman-adv/multicast.c | 18 ++++++++++-------- net/batman-adv/types.h | 2 +- 2 files changed, 11 insertions(+), 9 deletions(-) diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index 7aa480b7edd0..8f1ec21bf2d0 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -19,6 +19,7 @@ #include "main.h" #include +#include #include #include #include @@ -697,29 +698,30 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, uint8_t mcast_flags = BATADV_NO_FLAGS; bool orig_initialized; - orig_initialized = orig->capa_initialized & BATADV_ORIG_CAPA_HAS_MCAST; + orig_initialized = test_bit(BATADV_ORIG_CAPA_HAS_MCAST, + &orig->capa_initialized); /* If mcast support is turned on decrease the disabled mcast node * counter only if we had increased it for this node before. If this * is a completely new orig_node no need to decrease the counter. */ if (orig_mcast_enabled && - !(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST)) { + !test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities)) { 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. */ } else if (!orig_mcast_enabled && - (orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST || + (test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) || !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))) @@ -763,8 +765,8 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig) { struct batadv_priv *bat_priv = orig->bat_priv; - if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST) && - orig->capa_initialized & BATADV_ORIG_CAPA_HAS_MCAST) + if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) && + test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized)) atomic_dec(&bat_priv->mcast.num_disabled); batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 6f801efc3ae2..1eeed1847bc7 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -316,7 +316,7 @@ enum batadv_orig_capabilities { BATADV_ORIG_CAPA_HAS_DAT, BATADV_ORIG_CAPA_HAS_NC, BATADV_ORIG_CAPA_HAS_TT, - BATADV_ORIG_CAPA_HAS_MCAST = BIT(3), + BATADV_ORIG_CAPA_HAS_MCAST, }; /** -- 2.20.1