[PATCH] isdn/gigaset: use tasklet_kill in device remove/release process

[PATCH] isdn/gigaset: use tasklet_kill in device remove/release process

[Xiaotian Feng]

Some driver uses tasklet_disable in device remove/release process,
tasklet_disable will inc tasklet->count and return. If the tasklet
is not handled yet under some softirq pressure, the tasklet will be
placed on the tasklet_vec, never have a chance to be excuted. This might
lead to a heavy loaded ksoftirqd, wakeup with pending_softirq, but
tasklet is disabled. tasklet_kill should be used in this case.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Cc: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: gigaset307x-common@lists.sourceforge.net 
---
 drivers/isdn/gigaset/interface.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 67abf3f..284c7f3 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -544,7 +544,6 @@ void gigaset_if_free(struct cardstate *cs)
 	if (!drv->have_tty)
 		return;
 
-	tasklet_disable(&cs->if_wake_tasklet);
 	tasklet_kill(&cs->if_wake_tasklet);
 	cs->tty_dev = NULL;
 	tty_unregister_device(drv->tty, cs->minor_index);
-- 
1.7.9.5

Re: [PATCH] isdn/gigaset: use tasklet_kill in device remove/release process

[Tilman Schmidt]

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Am 31.10.2012 11:44, schrieb Xiaotian Feng:
> Some driver uses tasklet_disable in device remove/release process,
> tasklet_disable will inc tasklet->count and return. If the tasklet
> is not handled yet under some softirq pressure, the tasklet will be
> placed on the tasklet_vec, never have a chance to be excuted. This might
> lead to a heavy loaded ksoftirqd, wakeup with pending_softirq, but
> tasklet is disabled. tasklet_kill should be used in this case.
> 
> Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
> Cc: Hansjoerg Lipp <hjlipp@web.de>
> Cc: Tilman Schmidt <tilman@imap.cc>
> Cc: Karsten Keil <isdn@linux-pingi.de>
> Cc: gigaset307x-common@lists.sourceforge.net 
Acked-by: Tilman Schmidt <tilman@imap.cc>

> ---
>  drivers/isdn/gigaset/interface.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
> index 67abf3f..284c7f3 100644
> --- a/drivers/isdn/gigaset/interface.c
> +++ b/drivers/isdn/gigaset/interface.c
> @@ -544,7 +544,6 @@ void gigaset_if_free(struct cardstate *cs)
>  	if (!drv->have_tty)
>  		return;
>  
> -	tasklet_disable(&cs->if_wake_tasklet);
>  	tasklet_kill(&cs->if_wake_tasklet);
>  	cs->tty_dev = NULL;
>  	tty_unregister_device(drv->tty, cs->minor_index);
> 

-- 
Tilman Schmidt                    E-Mail: tilman@imap.cc
Bonn, Germany
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