[PATCH] mac80211: fix PS vs. scan race

[PATCH] mac80211: fix PS vs. scan race

[Johannes Berg]

When somebody changes the PS parameters while scanning
is in progress, we enable PS -- during the scan. This
is clearly not desirable, and we can just abort enabling
PS when scanning since when the scan finishes it will
be taken care of.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
---
 net/mac80211/mlme.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- wireless-testing.orig/net/mac80211/mlme.c	2009-04-22 22:57:45.000000000 +0200
+++ wireless-testing/net/mac80211/mlme.c	2009-04-22 22:58:56.000000000 +0200
@@ -487,6 +487,13 @@ static void ieee80211_enable_ps(struct i
 {
 	struct ieee80211_conf *conf = &local->hw.conf;
 
+	/*
+	 * If we are scanning right now then the parameters will
+	 * take effect when scan finishes.
+	 */
+	if (local->hw_scanning || local->sw_scanning)
+		return;
+
 	if (conf->dynamic_ps_timeout > 0 &&
 	    !(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)) {
 		mod_timer(&local->dynamic_ps_timer, jiffies +

Re: [PATCH] mac80211: fix PS vs. scan race

[Kalle Valo]

Johannes Berg <johannes@sipsolutions.net> writes:

> When somebody changes the PS parameters while scanning
> is in progress, we enable PS -- during the scan. This
> is clearly not desirable, and we can just abort enabling
> PS when scanning since when the scan finishes it will
> be taken care of.
>
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

Reviewed-by: Kalle Valo <kalle.valo@iki.fi>

-- 
Kalle Valo

Re: [PATCH] mac80211: fix PS vs. scan race

[Johannes Berg]

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On Wed, 2009-04-22 at 23:02 +0200, Johannes Berg wrote:
> When somebody changes the PS parameters while scanning
> is in progress, we enable PS -- during the scan. This
> is clearly not desirable, and we can just abort enabling
> PS when scanning since when the scan finishes it will
> be taken care of.

John, did this fall through the cracks? I see you included a patch from
today but not this :)

johannes

> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> ---
>  net/mac80211/mlme.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> --- wireless-testing.orig/net/mac80211/mlme.c	2009-04-22 22:57:45.000000000 +0200
> +++ wireless-testing/net/mac80211/mlme.c	2009-04-22 22:58:56.000000000 +0200
> @@ -487,6 +487,13 @@ static void ieee80211_enable_ps(struct i
>  {
>  	struct ieee80211_conf *conf = &local->hw.conf;
>  
> +	/*
> +	 * If we are scanning right now then the parameters will
> +	 * take effect when scan finishes.
> +	 */
> +	if (local->hw_scanning || local->sw_scanning)
> +		return;
> +
>  	if (conf->dynamic_ps_timeout > 0 &&
>  	    !(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)) {
>  		mod_timer(&local->dynamic_ps_timer, jiffies +
> 
> 
> --
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Re: [PATCH] mac80211: fix PS vs. scan race

[John W. Linville]

On Thu, Apr 30, 2009 at 11:27:44PM +0200, Johannes Berg wrote:
> On Wed, 2009-04-22 at 23:02 +0200, Johannes Berg wrote:
> > When somebody changes the PS parameters while scanning
> > is in progress, we enable PS -- during the scan. This
> > is clearly not desirable, and we can just abort enabling
> > PS when scanning since when the scan finishes it will
> > be taken care of.
> 
> John, did this fall through the cracks? I see you included a patch from
> today but not this :)

Looks like this one (on wireless-testing#master)?

commit da6cbb045d04706157d3117153b275ed9126bd1d
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Wed Apr 22 23:02:51 2009 +0200

    mac80211: fix PS vs. scan race
    
    When somebody changes the PS parameters while scanning
    is in progress, we enable PS -- during the scan. This
    is clearly not desirable, and we can just abort enabling
    PS when scanning since when the scan finishes it will
    be taken care of.
    
    Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
    Reviewed-by: Kalle Valo <kalle.valo@iki.fi>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.

Re: [PATCH] mac80211: fix PS vs. scan race

[Johannes Berg]

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On Thu, 2009-04-30 at 18:30 -0400, John W. Linville wrote:

> Looks like this one (on wireless-testing#master)?
> 
> commit da6cbb045d04706157d3117153b275ed9126bd1d
> Author: Johannes Berg <johannes@sipsolutions.net>
> Date:   Wed Apr 22 23:02:51 2009 +0200
> 
>     mac80211: fix PS vs. scan race

Sorry, looks like I never learn... The patch still applied (probably
with some fuzz) so I figured it wasn't in.

johannes

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