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* [PATCH] xen-fbfront: correct return value checks on xenbus_scanf()
@ 2016-07-07  7:48 Jan Beulich
  2016-07-07  9:46 ` [Xen-devel] " David Vrabel
  0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2016-07-07  7:48 UTC (permalink / raw)
  To: plagnioj, tomi.valkeinen
  Cc: Juergen Gross, xen-devel, Boris Ostrovsky, David Vrabel,
	linux-fbdev

Only a positive return value indicates success.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
 drivers/video/fbdev/xen-fbfront.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- 4.7-rc6-xenbus_scanf.orig/drivers/video/fbdev/xen-fbfront.c
+++ 4.7-rc6-xenbus_scanf/drivers/video/fbdev/xen-fbfront.c
@@ -658,13 +658,13 @@ InitWait:
 			goto InitWait; /* no InitWait seen yet, fudge it */
 
 		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-				 "request-update", "%d", &val) < 0)
+				 "request-update", "%d", &val) <= 0)
 			val = 0;
 		if (val)
 			info->update_wanted = 1;
 
 		if (xenbus_scanf(XBT_NIL, dev->otherend,
-				 "feature-resize", "%d", &val) < 0)
+				 "feature-resize", "%d", &val) <= 0)
 			val = 0;
 		info->feature_resize = val;
 		break;




^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [Xen-devel] [PATCH] xen-fbfront: correct return value checks on xenbus_scanf()
  2016-07-07  7:48 [PATCH] xen-fbfront: correct return value checks on xenbus_scanf() Jan Beulich
@ 2016-07-07  9:46 ` David Vrabel
  0 siblings, 0 replies; 2+ messages in thread
From: David Vrabel @ 2016-07-07  9:46 UTC (permalink / raw)
  To: Jan Beulich, plagnioj, tomi.valkeinen
  Cc: Juergen Gross, xen-devel, Boris Ostrovsky, David Vrabel,
	linux-fbdev

On 07/07/16 08:48, Jan Beulich wrote:
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> ---
>  drivers/video/fbdev/xen-fbfront.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> --- 4.7-rc6-xenbus_scanf.orig/drivers/video/fbdev/xen-fbfront.c
> +++ 4.7-rc6-xenbus_scanf/drivers/video/fbdev/xen-fbfront.c
> @@ -658,13 +658,13 @@ InitWait:
>  			goto InitWait; /* no InitWait seen yet, fudge it */
>  
>  		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> -				 "request-update", "%d", &val) < 0)
> +				 "request-update", "%d", &val) <= 0)
>  			val = 0;
>  		if (val)
>  			info->update_wanted = 1;
>  
>  		if (xenbus_scanf(XBT_NIL, dev->otherend,
> -				 "feature-resize", "%d", &val) < 0)
> +				 "feature-resize", "%d", &val) <= 0)

xenbus_scanf() has:

/* Single read and scanf: returns -errno or num scanned. */
...
        if (ret = 0)
                return -ERANGE;
...

So none of these patches are necessary.

David

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2016-07-07  7:48 [PATCH] xen-fbfront: correct return value checks on xenbus_scanf() Jan Beulich
2016-07-07  9:46 ` [Xen-devel] " David Vrabel

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