[03/10] batman-adv: Make DAT capability changes atomic
Commit Message
From: Linus Lüssing <linus.luessing@c0d3.blue>
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: 17cf0ea455f1 ("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>
---
net/batman-adv/distributed-arp-table.c | 7 ++++---
net/batman-adv/types.h | 4 ++--
2 files changed, 6 insertions(+), 5 deletions(-)
Comments
Hello.
On 08/11/2015 07:35 PM, Antonio Quartulli wrote:
> From: Linus Lüssing <linus.luessing@c0d3.blue>
> 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: 17cf0ea455f1 ("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>
> ---
> net/batman-adv/distributed-arp-table.c | 7 ++++---
> net/batman-adv/types.h | 4 ++--
> 2 files changed, 6 insertions(+), 5 deletions(-)
> diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
> index fb54e6a..244dcf6 100644
> --- a/net/batman-adv/distributed-arp-table.c
> +++ b/net/batman-adv/distributed-arp-table.c
[...]
> @@ -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)))
() around the tst_bit() call not needed.
[...]
MBR, Sergei
On 11/08/15 21:36, Sergei Shtylyov wrote:
>> /* 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)))
>
> () around the tst_bit() call not needed.
Thanks for the hint Sergei. Even if I don't remember having seen any
complaint from checkpatch.pl about this.
I'll resend the pull request with this fixed patches.
Cheers,
@@ -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);
}
/**
@@ -273,7 +273,7 @@ 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;
@@ -313,7 +313,7 @@ struct batadv_orig_node {
* (= orig node announces a tvlv of type BATADV_TVLV_MCAST)
*/
enum batadv_orig_capabilities {
- BATADV_ORIG_CAPA_HAS_DAT = BIT(0),
+ BATADV_ORIG_CAPA_HAS_DAT,
BATADV_ORIG_CAPA_HAS_NC = BIT(1),
BATADV_ORIG_CAPA_HAS_TT = BIT(2),
BATADV_ORIG_CAPA_HAS_MCAST = BIT(3),