[PATCH] mac80211: Fix the wrong WARN_ON message appearing on enabling power save.

[PATCH] mac80211: Fix the wrong WARN_ON message appearing on enabling power save.

[Vivek Natarajan]

The warning message intended to be hit on driver's rejection of a Tx frame
is also hit while the netif_subqueue is stopped. This patch fixes this error
case.

Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
---
 net/mac80211/tx.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index f1c726d..bf73f6d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -35,6 +35,7 @@
 #define IEEE80211_TX_OK		0
 #define IEEE80211_TX_AGAIN	1
 #define IEEE80211_TX_FRAG_AGAIN	2
+#define IEEE80211_TX_PENDING	3
 
 /* misc utils */
 
@@ -1085,7 +1086,7 @@ static int __ieee80211_tx(struct ieee80211_local *local, struct sk_buff *skb,
 
 	if (skb) {
 		if (netif_subqueue_stopped(local->mdev, skb))
-			return IEEE80211_TX_AGAIN;
+			return IEEE80211_TX_PENDING;
 
 		ret = local->ops->tx(local_to_hw(local), skb);
 		if (ret)
@@ -1211,8 +1212,9 @@ retry:
 		 * queues, there's no reason for a driver to reject
 		 * a frame there, warn and drop it.
 		 */
-		if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
-			goto drop;
+		if (ret != IEEE80211_TX_PENDING)
+			if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
+				goto drop;
 
 		store = &local->pending_packet[queue];
 
-- 
1.6.0.1

Re: [PATCH] mac80211: Fix the wrong WARN_ON message appearing on enabling power save.

[Johannes Berg]

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On Thu, 2009-02-05 at 16:36 +0530, Vivek Natarajan wrote:
> The warning message intended to be hit on driver's rejection of a Tx frame
> is also hit while the netif_subqueue is stopped. This patch fixes this error
> case.

This seems a little odd. Why would we be in that code if the queue is
stopped?

> Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
> ---
>  net/mac80211/tx.c |    8 +++++---
>  1 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index f1c726d..bf73f6d 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -35,6 +35,7 @@
>  #define IEEE80211_TX_OK		0
>  #define IEEE80211_TX_AGAIN	1
>  #define IEEE80211_TX_FRAG_AGAIN	2
> +#define IEEE80211_TX_PENDING	3
>  
>  /* misc utils */
>  
> @@ -1085,7 +1086,7 @@ static int __ieee80211_tx(struct ieee80211_local *local, struct sk_buff *skb,
>  
>  	if (skb) {
>  		if (netif_subqueue_stopped(local->mdev, skb))
> -			return IEEE80211_TX_AGAIN;
> +			return IEEE80211_TX_PENDING;
>  
>  		ret = local->ops->tx(local_to_hw(local), skb);
>  		if (ret)
> @@ -1211,8 +1212,9 @@ retry:
>  		 * queues, there's no reason for a driver to reject
>  		 * a frame there, warn and drop it.
>  		 */
> -		if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
> -			goto drop;
> +		if (ret != IEEE80211_TX_PENDING)
> +			if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
> +				goto drop;
>  
>  		store = &local->pending_packet[queue];
>  

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Re: [PATCH] mac80211: Fix the wrong WARN_ON message appearing on enabling power save.

[Vivek Natarajan]

On Thu, Feb 5, 2009 at 5:37 PM, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Thu, 2009-02-05 at 16:36 +0530, Vivek Natarajan wrote:
>> The warning message intended to be hit on driver's rejection of a Tx frame
>> is also hit while the netif_subqueue is stopped. This patch fixes this error
>> case.
>
> This seems a little odd. Why would we be in that code if the queue is
> stopped?

This issue happens only when we are associated with a 11n AP and power
save is enabled.
In the function 'ieee80211_master_start_xmit', ps_disable_work is
queued where wake_queues is called. But before this work is executed,
we check if the queues are stopped in _ieee80211_tx and returned
TX_AGAIN to ieee8011_tx which led to the warning message.

Vivek.

Re: [PATCH] mac80211: Fix the wrong WARN_ON message appearing on enabling power save.

[Johannes Berg]

[-- Attachment #1: Type: text/plain, Size: 951 bytes --]

On Thu, 2009-02-05 at 17:56 +0530, Vivek Natarajan wrote:
> On Thu, Feb 5, 2009 at 5:37 PM, Johannes Berg <johannes@sipsolutions.net> wrote:
> > On Thu, 2009-02-05 at 16:36 +0530, Vivek Natarajan wrote:
> >> The warning message intended to be hit on driver's rejection of a Tx frame
> >> is also hit while the netif_subqueue is stopped. This patch fixes this error
> >> case.
> >
> > This seems a little odd. Why would we be in that code if the queue is
> > stopped?
> 
> This issue happens only when we are associated with a 11n AP and power
> save is enabled.
> In the function 'ieee80211_master_start_xmit', ps_disable_work is
> queued where wake_queues is called. But before this work is executed,
> we check if the queues are stopped in _ieee80211_tx and returned
> TX_AGAIN to ieee8011_tx which led to the warning message.

Ah, ok, thanks for the explanation. Might make sense to put that into
the commit message.

johannes

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[PATCH] mac80211: Fix the wrong WARN_ON message appearing on enabling power save.

[Vivek Natarajan]

This issue happens only when we are associated with a 11n AP and power save
is enabled. In the function 'ieee80211_master_start_xmit', ps_disable_work
is queued where wake_queues is called. But before this work is executed,
we check if the queues are stopped in _ieee80211_tx and return TX_AGAIN to
ieee8011_tx which leads to the warning message.
This patch fixes this erroneous case.

Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
---
 net/mac80211/tx.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index f1c726d..bf73f6d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -35,6 +35,7 @@
 #define IEEE80211_TX_OK		0
 #define IEEE80211_TX_AGAIN	1
 #define IEEE80211_TX_FRAG_AGAIN	2
+#define IEEE80211_TX_PENDING	3
 
 /* misc utils */
 
@@ -1085,7 +1086,7 @@ static int __ieee80211_tx(struct ieee80211_local *local, struct sk_buff *skb,
 
 	if (skb) {
 		if (netif_subqueue_stopped(local->mdev, skb))
-			return IEEE80211_TX_AGAIN;
+			return IEEE80211_TX_PENDING;
 
 		ret = local->ops->tx(local_to_hw(local), skb);
 		if (ret)
@@ -1211,8 +1212,9 @@ retry:
 		 * queues, there's no reason for a driver to reject
 		 * a frame there, warn and drop it.
 		 */
-		if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
-			goto drop;
+		if (ret != IEEE80211_TX_PENDING)
+			if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
+				goto drop;
 
 		store = &local->pending_packet[queue];
 
-- 
1.6.0.1