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[v4,maint,2/5] batman-adv: Make NC capability changes atomic

Message ID 1434467426-4281-3-git-send-email-linus.luessing@c0d3.blue
State Accepted, archived
Headers show

Commit Message

Linus Lüssing June 16, 2015, 3:10 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: 7dd9d8992b0c ("batman-adv: tvlv - add network coding container")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 network-coding.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Marek Lindner June 17, 2015, 10:37 a.m. UTC | #1
On Tuesday, June 16, 2015 17:10:23 Linus Lüssing wrote:
> 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: 7dd9d8992b0c ("batman-adv: tvlv - add network coding container")
> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
> ---
>  network-coding.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied in revision 586df9e.

Thanks,
Marek
diff mbox

Patch

diff --git a/network-coding.c b/network-coding.c
index 89e1d47..3ce493e 100644
--- a/network-coding.c
+++ b/network-coding.c
@@ -105,9 +105,9 @@  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);
 }
 
 /**