Commit ff595325 authored by Jan Beulich's avatar Jan Beulich Committed by Konrad Rzeszutek Wilk
Browse files

xen-blkfront: prefer xenbus_scanf() over xenbus_gather() 



... 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.

Acked-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
Acked-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 6694389a

drivers/block/xen-blkfront.c

+19 −24
Original line number Diff line number Diff line
@@ -2208,10 +2208,9 @@ static void blkfront_setup_discard(struct blkfront_info *info) 
		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_features(struct blkfront_info *info) 


	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_features(struct blkfront_info *info) 
	 *

	 * 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,

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