[PATCH net-next] bridge: Fix incorrect judgment of promisc

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index a08d2b8..6a07a40 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c

@@ -153,7 +153,7 @@ 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 <= !!br_auto_port(p))
 				br_port_clear_promisc(p);
 			else
 				br_port_set_promisc(p);

-- 
1.8.1.2

From: Toshiaki Makita

Why not the less confusing:
			if (br->auto_cnt || br_auto_port(p))
and reverse the then/else lines?

	David

(2014/06/05 20:03), David Laight wrote:

From: Toshiaki Makita

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index a08d2b8..6a07a40 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c

@@ -153,7 +153,7 @@ 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 <= !!br_auto_port(p))
 				br_port_clear_promisc(p);
 			else
 				br_port_set_promisc(p);

Why not the less confusing:
			if (br->auto_cnt || br_auto_port(p))
and reverse the then/else lines?

I'm respecting the original style, but I'm not particular about this style.
I'll make less confusing one, thanks :)

(Your suggested condition is not exactly the same as current one, even
if reversing if/else. v2 will be different than it. Anyway, thanks.)

Toshiaki Makita

From: Toshiaki Makita

(2014/06/05 20:03), David Laight wrote:

quoted

From: Toshiaki Makita

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index a08d2b8..6a07a40 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c

@@ -153,7 +153,7 @@ 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 <= !!br_auto_port(p))
 				br_port_clear_promisc(p);
 			else
 				br_port_set_promisc(p);

Why not the less confusing:
			if (br->auto_cnt || br_auto_port(p))
and reverse the then/else lines?

I'm respecting the original style, but I'm not particular about this style.
I'll make less confusing one, thanks :)

(Your suggested condition is not exactly the same as current one, even
if reversing if/else. v2 will be different than it. Anyway, thanks.)

A quick truth table:
	auto_cnt	auto_port	set/clear
		0		0	clear
		0		1	clear
		1		0	set
		1		1	clear
		2+		0/1	clear

So you want:
	if (br->auto_cnt && !br_auto_port(p))
		br_port_set_promisc(p);
	else
		br_port_clear_promisc(p);

Does seem like a strange condition.

	David

	

(2014/06/05 21:55), David Laight wrote:

From: Toshiaki Makita

quoted

(2014/06/05 20:03), David Laight wrote:

quoted

From: Toshiaki Makita

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index a08d2b8..6a07a40 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c

@@ -153,7 +153,7 @@ 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 <= !!br_auto_port(p))
 				br_port_clear_promisc(p);
 			else
 				br_port_set_promisc(p);

Why not the less confusing:
			if (br->auto_cnt || br_auto_port(p))
and reverse the then/else lines?

I'm respecting the original style, but I'm not particular about this style.
I'll make less confusing one, thanks :)

(Your suggested condition is not exactly the same as current one, even
if reversing if/else. v2 will be different than it. Anyway, thanks.)

A quick truth table:
	auto_cnt	auto_port	set/clear
		0		0	clear
		0		1	clear
		1		0	set
		1		1	clear
		2+		0/1	clear

The last line should be set.

Thanks,
Toshiaki Makita

So you want:
	if (br->auto_cnt && !br_auto_port(p))
		br_port_set_promisc(p);
	else
		br_port_clear_promisc(p);

Does seem like a strange condition.

	David

From: Toshiaki Makita 

quoted

A quick truth table:
	auto_cnt	auto_port	set/clear
		0		0	clear
		0		1	clear
		1		0	set
		1		1	clear
		2+		0/1	clear

The last line should be set.

I've clearly not drunk enough coffee today...

I suspect the 0-1 line is impossible.
Since the check is probably for 'any other ports in 'auto' mode'.
So:
	if (auto_cnt - auto_port > 0)
(which is much the same as the original) is a good descriptive test.

	David

On 06/05/2014 08:55 AM, David Laight wrote:

From: Toshiaki Makita

quoted

(2014/06/05 20:03), David Laight wrote:

quoted

From: Toshiaki Makita

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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index a08d2b8..6a07a40 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c

@@ -153,7 +153,7 @@ 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 <= !!br_auto_port(p))
 				br_port_clear_promisc(p);
 			else
 				br_port_set_promisc(p);

Why not the less confusing:
			if (br->auto_cnt || br_auto_port(p))
and reverse the then/else lines?

I'm respecting the original style, but I'm not particular about this style.
I'll make less confusing one, thanks :)

(Your suggested condition is not exactly the same as current one, even
if reversing if/else. v2 will be different than it. Anyway, thanks.)

A quick truth table:
	auto_cnt	auto_port	set/clear
		0		0	clear
		0		1	clear

               Can't happen

		1		0	set

              Can't happen

		1		1	clear
		2+		0/1	clear

So you want:
	if (br->auto_cnt && !br_auto_port(p))
		br_port_set_promisc(p);
	else
		br_port_clear_promisc(p);

Some versions of the series that added this had
an explicit check for count.  Essentially, the
expanded condition is this:

  if (count == 0)
     clear
  else if (count == 1 && auto_port(p))
     clear
  else
     set

The suggestion was that we could use a boolean (0|1)
to check reduce the above to
  if (count <= auto_port(p))
     clear
  else
     set

Personally, I prefer the extended version since it
is much clearer and is easy to understand.

-vlad

Does seem like a strange condition.

	David

	


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