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: 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>
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index f0a50f3..4660401 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -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 @@
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 @@
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 */