[PATCH] xen-fbfront: correct return value checks on xenbus_scanf()

STALE3683d

2 messages, 2 authors, 2016-07-07 · open the first message on its own page

[PATCH] xen-fbfront: correct return value checks on xenbus_scanf()

From: Jan Beulich <hidden>
Date: 2016-07-07 07:48:53

Only a positive return value indicates success.

Signed-off-by: Jan Beulich <redacted>
---
 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;


Re: [Xen-devel] [PATCH] xen-fbfront: correct return value checks on xenbus_scanf()

From: David Vrabel <hidden>
Date: 2016-07-07 09:46:07

On 07/07/16 08:48, Jan Beulich wrote:
quoted hunk
Signed-off-by: Jan Beulich <redacted>
---
 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
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