From 505f068df9dd37bfa86114f746bacedc2b32437a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Linus=20L=C3=BCssing?= <linus.luessing@c0d3.blue> Date: Tue, 16 Jun 2015 17:10:23 +0200 Subject: [PATCH] batman-adv: Make NC capability changes atomic MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 4635469f5c617282f18c69643af36cd8c0acf707 upstream. 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: 3f4841ffb336 ("batman-adv: tvlv - add network coding container") Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/batman-adv/network-coding.c | 7 ++++--- net/batman-adv/types.h | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c index 127cc4d7380a..a449195c5b2b 100644 --- a/net/batman-adv/network-coding.c +++ b/net/batman-adv/network-coding.c @@ -15,6 +15,7 @@ * along with this program; if not, see <http://www.gnu.org/licenses/>. */ +#include <linux/bitops.h> #include <linux/debugfs.h> #include "main.h" @@ -105,9 +106,9 @@ static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, uint16_t tvlv_value_len) { if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) - orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_NC; + clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities); else - orig->capabilities |= BATADV_ORIG_CAPA_HAS_NC; + set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities); } /** @@ -871,7 +872,7 @@ void batadv_nc_update_nc_node(struct batadv_priv *bat_priv, goto out; /* check if orig node is network coding enabled */ - if (!(orig_node->capabilities & BATADV_ORIG_CAPA_HAS_NC)) + if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities)) goto out; /* accept ogms from 'good' neighbors and single hop neighbors */ diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 4fff13cc66b4..767390318c86 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -297,7 +297,7 @@ struct batadv_orig_node { */ enum batadv_orig_capabilities { BATADV_ORIG_CAPA_HAS_DAT, - BATADV_ORIG_CAPA_HAS_NC = BIT(1), + BATADV_ORIG_CAPA_HAS_NC, BATADV_ORIG_CAPA_HAS_TT = BIT(2), BATADV_ORIG_CAPA_HAS_MCAST = BIT(3), }; -- 2.30.9