Patch "batman-adv: Make NC capability changes atomic" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

batman-adv: Make NC capability changes atomic

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
batman-adv-make-nc-capability-changes-atomic.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?Linus=20L=C3=BCssing?= <[email protected]>
Date: Tue, 16 Jun 2015 17:10:23 +0200
Subject: batman-adv: Make NC capability changes atomic
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From: =?UTF-8?q?Linus=20L=C3=BCssing?= <[email protected]>

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.

---
 net/batman-adv/network-coding.c |    7 ++++---
 net/batman-adv/types.h          |    2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

@@ -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_v
 					  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 bat
 		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 */

@@ -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),
 };

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/batman-adv-fix-potential-synchronization-issues-in-mcast-tvlv-handler.patch queue-4.1/batman-adv-make-tt-capability-changes-atomic.patch queue-4.1/batman-adv-make-dat-capability-changes-atomic.patch queue-4.1/batman-adv-make-nc-capability-changes-atomic.patch queue-4.1/batman-adv-fix-potentially-broken-skb-network-header-access.patch queue-4.1/batman-adv-make-mcast-capability-changes-atomic.patch