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* [PATCH] i40iw: Remove unnecessary synchronize_irq() before free_irq()
@ 2016-03-28  9:31 Lars-Peter Clausen
       [not found] ` <1459157486-23257-1-git-send-email-lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
  0 siblings, 1 reply; 3+ messages in thread
From: Lars-Peter Clausen @ 2016-03-28  9:31 UTC (permalink / raw)
  To: Doug Ledford
  Cc: Faisal Latif, Chien Tin Tung, Mustafa Ismail, Shiraz Saleem,
	Tatyana Nikolova, Sean Hefty, Hal Rosenstock,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA, Lars-Peter Clausen

Calling synchronize_irq() right before free_irq() is quite useless. On one
hand the IRQ can easily fire again before free_irq() is entered, on the
other hand free_irq() itself calls synchronize_irq() internally (in a race
condition free way), before any state associated with the IRQ is freed.

Patch was generated using the following semantic patch:
// <smpl>
@@
expression irq;
@@
-synchronize_irq(irq);
 free_irq(irq, ...);
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
---
 drivers/infiniband/hw/i40iw/i40iw_main.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/infiniband/hw/i40iw/i40iw_main.c b/drivers/infiniband/hw/i40iw/i40iw_main.c
index 90e5af2..006c44f 100644
--- a/drivers/infiniband/hw/i40iw/i40iw_main.c
+++ b/drivers/infiniband/hw/i40iw/i40iw_main.c
@@ -270,7 +270,6 @@ static void i40iw_disable_irq(struct i40iw_sc_dev *dev,
 		i40iw_wr32(dev->hw, I40E_PFINT_DYN_CTLN(msix_vec->idx - 1), 0);
 	else
 		i40iw_wr32(dev->hw, I40E_VFINT_DYN_CTLN1(msix_vec->idx - 1), 0);
-	synchronize_irq(msix_vec->irq);
 	free_irq(msix_vec->irq, dev_id);
 }
 
-- 
2.1.4

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^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] i40iw: Remove unnecessary synchronize_irq() before free_irq()
       [not found] ` <1459157486-23257-1-git-send-email-lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
@ 2016-03-30  7:15   ` Leon Romanovsky
       [not found]     ` <20160330071503.GB8511-2ukJVAZIZ/Y@public.gmane.org>
  0 siblings, 1 reply; 3+ messages in thread
From: Leon Romanovsky @ 2016-03-30  7:15 UTC (permalink / raw)
  To: Lars-Peter Clausen
  Cc: Doug Ledford, Faisal Latif, Chien Tin Tung, Mustafa Ismail,
	Shiraz Saleem, Tatyana Nikolova, Sean Hefty, Hal Rosenstock,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA

On Mon, Mar 28, 2016 at 11:31:26AM +0200, Lars-Peter Clausen wrote:
> Calling synchronize_irq() right before free_irq() is quite useless. On one
> hand the IRQ can easily fire again before free_irq() is entered, on the
> other hand free_irq() itself calls synchronize_irq() internally (in a race
> condition free way), before any state associated with the IRQ is freed.
> 
> Patch was generated using the following semantic patch:
> // <smpl>
> @@
> expression irq;
> @@
> -synchronize_irq(irq);
>  free_irq(irq, ...);
> // </smpl>
> 
> Signed-off-by: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>

Thanks
Reviewed-by: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

> ---
>  drivers/infiniband/hw/i40iw/i40iw_main.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/infiniband/hw/i40iw/i40iw_main.c b/drivers/infiniband/hw/i40iw/i40iw_main.c
> index 90e5af2..006c44f 100644
> --- a/drivers/infiniband/hw/i40iw/i40iw_main.c
> +++ b/drivers/infiniband/hw/i40iw/i40iw_main.c
> @@ -270,7 +270,6 @@ static void i40iw_disable_irq(struct i40iw_sc_dev *dev,
>  		i40iw_wr32(dev->hw, I40E_PFINT_DYN_CTLN(msix_vec->idx - 1), 0);
>  	else
>  		i40iw_wr32(dev->hw, I40E_VFINT_DYN_CTLN1(msix_vec->idx - 1), 0);
> -	synchronize_irq(msix_vec->irq);
>  	free_irq(msix_vec->irq, dev_id);
>  }
>  
> -- 
> 2.1.4
> 
> --
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> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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--
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^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] i40iw: Remove unnecessary synchronize_irq() before free_irq()
       [not found]     ` <20160330071503.GB8511-2ukJVAZIZ/Y@public.gmane.org>
@ 2016-04-07 18:27       ` Faisal Latif
  0 siblings, 0 replies; 3+ messages in thread
From: Faisal Latif @ 2016-04-07 18:27 UTC (permalink / raw)
  To: Lars-Peter Clausen, Doug Ledford, Chien Tin Tung, Mustafa Ismail,
	Shiraz Saleem, Tatyana Nikolova, Sean Hefty, Hal Rosenstock,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA

On Wed, Mar 30, 2016 at 10:15:03AM +0300, Leon Romanovsky wrote:
> On Mon, Mar 28, 2016 at 11:31:26AM +0200, Lars-Peter Clausen wrote:
> > Calling synchronize_irq() right before free_irq() is quite useless. On one
> > hand the IRQ can easily fire again before free_irq() is entered, on the
> > other hand free_irq() itself calls synchronize_irq() internally (in a race
> > condition free way), before any state associated with the IRQ is freed.
> > 
> > Patch was generated using the following semantic patch:
> > // <smpl>
> > @@
> > expression irq;
> > @@
> > -synchronize_irq(irq);
> >  free_irq(irq, ...);
> > // </smpl>
> > 
> > Signed-off-by: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
> 
> Thanks
> Reviewed-by: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> 

Thanks
Acked-by: Faisal Latif <faisal.latif#intel.com>

> > ---
> >  drivers/infiniband/hw/i40iw/i40iw_main.c | 1 -
> >  1 file changed, 1 deletion(-)
> > 
> > diff --git a/drivers/infiniband/hw/i40iw/i40iw_main.c b/drivers/infiniband/hw/i40iw/i40iw_main.c
> > index 90e5af2..006c44f 100644
> > --- a/drivers/infiniband/hw/i40iw/i40iw_main.c
> > +++ b/drivers/infiniband/hw/i40iw/i40iw_main.c
> > @@ -270,7 +270,6 @@ static void i40iw_disable_irq(struct i40iw_sc_dev *dev,
> >  		i40iw_wr32(dev->hw, I40E_PFINT_DYN_CTLN(msix_vec->idx - 1), 0);
> >  	else
> >  		i40iw_wr32(dev->hw, I40E_VFINT_DYN_CTLN1(msix_vec->idx - 1), 0);
> > -	synchronize_irq(msix_vec->irq);
> >  	free_irq(msix_vec->irq, dev_id);
> >  }
> >  
> > -- 
> > 2.1.4
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
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^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-04-07 18:27 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-03-28  9:31 [PATCH] i40iw: Remove unnecessary synchronize_irq() before free_irq() Lars-Peter Clausen
     [not found] ` <1459157486-23257-1-git-send-email-lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
2016-03-30  7:15   ` Leon Romanovsky
     [not found]     ` <20160330071503.GB8511-2ukJVAZIZ/Y@public.gmane.org>
2016-04-07 18:27       ` Faisal Latif

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