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batman-adv: Make DAT capability changes atomic

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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: 17cf0ea455 ("batman-adv: tvlv - add distributed arp table 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 17:10:22 +02:00
committed by Antonio Quartulli
parent 571a963768
commit 65d7d46050
2 changed files with 6 additions and 5 deletions
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7
net/batman-adv/distributed-arp-table.c
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@@ -19,6 +19,7 @@
#include "main.h"
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/byteorder/generic.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
@@ -453,7 +454,7 @@ static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res,
int j;
/* check if orig node candidate is running DAT */
if (!(candidate->capabilities & BATADV_ORIG_CAPA_HAS_DAT))
if (!test_bit(BATADV_ORIG_CAPA_HAS_DAT, &candidate->capabilities))
goto out;
/* Check if this node has already been selected... */
@@ -713,9 +714,9 @@ static void batadv_dat_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_DAT;
clear_bit(BATADV_ORIG_CAPA_HAS_DAT, &orig->capabilities);
else
orig->capabilities |= BATADV_ORIG_CAPA_HAS_DAT;
set_bit(BATADV_ORIG_CAPA_HAS_DAT, &orig->capabilities);
}
/**