On 06/05/2014 09:01 AM, Toshiaki Makita wrote:

(2014/06/05 21:30), Michael S. Tsirkin wrote:

quoted

On Thu, Jun 05, 2014 at 08:53:32PM +0900, Toshiaki Makita wrote:

quoted

br_manage_promisc() incorrectly expects br_auto_port() to return only 0
or 1, while it actually returns flags, i.e., a subset of BR_AUTO_MASK.

Signed-off-by: Toshiaki Makita <redacted>
---
 net/bridge/br_if.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index a08d2b8..3eca3fd 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c

@@ -153,7 +153,8 @@ void br_manage_promisc(struct net_bridge *br)
 			 * This lets us disable promiscuous mode and write
 			 * this config to hw.
 			 */
-			if (br->auto_cnt <= br_auto_port(p))
+			if (br->auto_cnt == 0 ||
+			    (br->auto_cnt == 1 && br_auto_port(p)))
 				br_port_clear_promisc(p);
 			else
 				br_port_set_promisc(p);

It's all a nasty side-effect of using macros IMHO.

How about we just make these inline functions returning bool?

The bugfix will fall out naturally.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Warning: untested.

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 53d6e32..5818dd2 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h

@@ -200,8 +200,15 @@ struct net_bridge_port
 #endif
 };
 
-#define br_auto_port(p) ((p)->flags & BR_AUTO_MASK)
-#define br_promisc_port(p) ((p)->flags & BR_PROMISC)
+static inline bool br_auto_port(struct net_bridge_port *p)
+{
+	return p->flags & BR_AUTO_MASK;
+}
+
+static inline bool br_promisc_port(struct net_bridge_port *p)
+{
+	return p->flags & BR_PROMISC;
+}
 
 #define br_port_exists(dev) (dev->priv_flags & IFF_BRIDGE_PORT)

This also looks good.

IMHO, the caller side should not assume these macros (or inline
functions) return boolean value.  There exists similar macro such as
br_port_exists() that doesn't return boolean.

Ohterwise, we should change all macros into boolean functions, but it
might affect performance a little if such a macro is used in fast path?
(I'm worried about the cost of casting non-zero values into 1.)

The following works correctly for me:
#define br_auto_port(p) !!((p)->flags & BR_AUTO_MASK)

Small test shows:

printf("%d\n", br_auto_port(0x20);
1 <-- correct.  learning is set.

printf("%d\n", br_auto_port(0x40);
1 <-- correct.  flooding is set.

printf("%d\n", br_auto_port(0x60);
1 <-- correct, both are set.

printf("%d\n", br_auto_port(0x08);
0 <-- correct.  neither are set.

-vlad

Thanks,
Toshiaki Makita
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