From: "Jan Beulich" <JBeulich@suse.com>
To: Roger Pau Monne <roger.pau@citrix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Subject: [PATCH] xen-blkfront: prefer xenbus_scanf() over xenbus_gather()
Date: Thu, 07 Jul 2016 02:05:46 -0600 [thread overview]
Message-ID: <577E297A02000078000FBF20__6983.64654458619$1467878806$gmane$org@prv-mh.provo.novell.com> (raw)
... for single items being collected: It is more typesafe (as the
compiler can check format string and to-be-written-to variable match)
and requires one less parameter to be passed.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
drivers/block/xen-blkfront.c | 43 +++++++++++++++++++------------------------
1 file changed, 19 insertions(+), 24 deletions(-)
--- 4.7-rc6-prefer-xenbus_scanf.orig/drivers/block/xen-blkfront.c
+++ 4.7-rc6-prefer-xenbus_scanf/drivers/block/xen-blkfront.c
@@ -2208,10 +2208,9 @@ static void blkfront_setup_discard(struc
info->discard_granularity = discard_granularity;
info->discard_alignment = discard_alignment;
}
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "discard-secure", "%d", &discard_secure,
- NULL);
- if (!err)
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "discard-secure", "%u", &discard_secure);
+ if (err > 0)
info->feature_secdiscard = !!discard_secure;
}
@@ -2310,9 +2309,8 @@ static void blkfront_gather_backend_feat
info->feature_flush = 0;
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-barrier", "%d", &barrier,
- NULL);
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "feature-barrier", "%d", &barrier);
/*
* If there's no "feature-barrier" defined, then it means
@@ -2321,38 +2319,35 @@ static void blkfront_gather_backend_feat
*
* If there are barriers, then we use flush.
*/
- if (!err && barrier)
+ if (err > 0 && barrier)
info->feature_flush = REQ_FLUSH | REQ_FUA;
/*
* And if there is "feature-flush-cache" use that above
* barriers.
*/
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-flush-cache", "%d", &flush,
- NULL);
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "feature-flush-cache", "%d", &flush);
- if (!err && flush)
+ if (err > 0 && flush)
info->feature_flush = REQ_FLUSH;
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-discard", "%d", &discard,
- NULL);
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "feature-discard", "%d", &discard);
- if (!err && discard)
+ if (err > 0 && discard)
blkfront_setup_discard(info);
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-persistent", "%u", &persistent,
- NULL);
- if (err)
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "feature-persistent", "%d", &persistent);
+ if (err <= 0)
info->feature_persistent = 0;
else
info->feature_persistent = persistent;
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-max-indirect-segments", "%u", &indirect_segments,
- NULL);
- if (err)
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "feature-max-indirect-segments", "%u",
+ &indirect_segments);
+ if (err <= 0)
info->max_indirect_segments = 0;
else
info->max_indirect_segments = min(indirect_segments,
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
next reply other threads:[~2016-07-07 8:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-07 8:05 Jan Beulich [this message]
[not found] <577E297A02000078000FBF20@prv-mh.provo.novell.com>
2016-07-07 9:40 ` [PATCH] xen-blkfront: prefer xenbus_scanf() over xenbus_gather() Roger Pau Monne
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='577E297A02000078000FBF20__6983.64654458619$1467878806$gmane$org@prv-mh.provo.novell.com' \
--to=jbeulich@suse.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=roger.pau@citrix.com \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).