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batman-adv: Make NC capability changes atomic 

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: 3f4841ffb3 ("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>
This commit is contained in:
Linus Lüssing 2015-06-16 17:10:23 +02:00 committed by Antonio Quartulli
parent 65d7d46050
commit 4635469f5c
2 changed files with 5 additions and 4 deletions
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7
net/batman-adv/network-coding.c
View File

@ -19,6 +19,7 @@
#include "main.h"
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/byteorder/generic.h>
#include <linux/compiler.h>
#include <linux/debugfs.h>
@ -134,9 +135,9 @@ 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);
}
/**
@ -894,7 +895,7 @@ 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 */

2
net/batman-adv/types.h
View File

@ -314,7 +314,7 @@ 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),
};