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[v3,maint,1/5] batman-adv: Make DAT capability changes atomic

Message ID 1434460643-3681-2-git-send-email-linus.luessing@c0d3.blue
State Superseded, archived
Headers show

Commit Message

Linus Lüssing June 16, 2015, 1:17 p.m. UTC
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() functions.

Fixes: 2b1c07b918d2 ("batman-adv: tvlv - add distributed arp table container")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 distributed-arp-table.c |    4 ++--
 types.h                 |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
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Patch

diff --git a/distributed-arp-table.c b/distributed-arp-table.c
index 0d791dc..b2cc19b 100644
--- a/distributed-arp-table.c
+++ b/distributed-arp-table.c
@@ -682,9 +682,9 @@  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);
 }
 
 /**
diff --git a/types.h b/types.h
index 28f2461..e33b5aa 100644
--- a/types.h
+++ b/types.h
@@ -256,7 +256,7 @@  struct batadv_orig_node {
 	struct hlist_node mcast_want_all_ipv4_node;
 	struct hlist_node mcast_want_all_ipv6_node;
 #endif
-	uint8_t capabilities;
+	unsigned long capabilities;
 	uint8_t capa_initialized;
 	atomic_t last_ttvn;
 	unsigned char *tt_buff;