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From: "Jan Beulich" <JBeulich@suse.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: Juergen Gross <JGross@suse.com>,
	xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com,
	david.vrabel@citrix.com, netdev@vger.kernel.org
Subject: [PATCH v2 4/4] xen-netback: prefer xenbus_scanf() over xenbus_gather()
Date: Fri, 08 Jul 2016 06:28:58 -0600	[thread overview]
Message-ID: <577FB8AA02000078000FCA21__34458.1625344746$1467981002$gmane$org@prv-mh.provo.novell.com> (raw)
In-Reply-To: <577FB70002000078000FC9FA@prv-mh.provo.novell.com>

For single items being collected this should be preferred as being more
typesafe (as the compiler can check format string and to-be-written-to
variable match) and more efficient (requiring one less parameter to be
passed).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Avoid commit message to continue from subject.
---
 drivers/net/xen-netback/xenbus.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- 4.7-rc6-prefer-xenbus_scanf.orig/drivers/net/xen-netback/xenbus.c
+++ 4.7-rc6-prefer-xenbus_scanf/drivers/net/xen-netback/xenbus.c
@@ -842,16 +842,16 @@ static int connect_ctrl_ring(struct back
 	unsigned int evtchn;
 	int err;
 
-	err = xenbus_gather(XBT_NIL, dev->otherend,
-			    "ctrl-ring-ref", "%u", &val, NULL);
-	if (err)
+	err = xenbus_scanf(XBT_NIL, dev->otherend,
+			   "ctrl-ring-ref", "%u", &val);
+	if (err <= 0)
 		goto done; /* The frontend does not have a control ring */
 
 	ring_ref = val;
 
-	err = xenbus_gather(XBT_NIL, dev->otherend,
-			    "event-channel-ctrl", "%u", &val, NULL);
-	if (err) {
+	err = xenbus_scanf(XBT_NIL, dev->otherend,
+			   "event-channel-ctrl", "%u", &val);
+	if (err <= 0) {
 		xenbus_dev_fatal(dev, err,
 				 "reading %s/event-channel-ctrl",
 				 dev->otherend);
@@ -872,7 +872,7 @@ done:
 	return 0;
 
 fail:
-	return err;
+	return err ?: -ENODATA;
 }
 
 static void connect(struct backend_info *be)




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  parent reply	other threads:[~2016-07-08 12:29 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <577FB70002000078000FC9FA@prv-mh.provo.novell.com>
2016-07-08 12:25 ` [PATCH v2 1/4] xenbus: prefer xenbus_scanf() over xenbus_gather() Jan Beulich
2016-07-08 12:26 ` [PATCH v2 2/4] xen-blkback: " Jan Beulich
2016-07-08 12:27 ` [PATCH v2 3/4] xen-blkfront: " Jan Beulich
2016-07-08 12:28 ` Jan Beulich [this message]
2016-07-08 14:17 ` [PATCH v2 0/4] xen: " Konrad Rzeszutek Wilk
2016-07-08 15:06   ` Jan Beulich
     [not found]   ` <577FDD9C02000078000FCBEB@prv-mh.provo.novell.com>
2016-07-08 15:12     ` Konrad Rzeszutek Wilk
2016-07-08 15:41   ` David Vrabel
     [not found]   ` <577FC9A0.9080407@citrix.com>
2016-07-08 15:54     ` Konrad Rzeszutek Wilk
     [not found] ` <577FB8AA02000078000FCA21@prv-mh.provo.novell.com>
2016-07-08 16:14   ` [PATCH v2 4/4] xen-netback: " Wei Liu

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