Re: [PATCH] xen-fbfront: correct return value checks on xenbus_scanf()
From: Juergen Gross <jgross@suse.com>
Date: 2016-07-07 09:42:53
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xen-devel
On 07/07/16 09:48, Jan Beulich wrote:
Only a positive return value indicates success.
Hmm, I'm not convinced on this change (and the similar others as well). From xenbus.h: /* Single read and scanf: returns -errno or num scanned if > 0. */ There should be no case for xenbus_scanf() returning 0. And looking into the functions proofs this is correct. Juergen
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) val = 0; info->feature_resize = val; break;