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Commit f27dc1ac authored by Juergen Gross's avatar Juergen Gross
Browse files

xen: make use of xenbus_read_unsigned() in xen-blkfront 



Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Acked-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 8235777b

drivers/block/xen-blkfront.c

+26 −55
Original line number Diff line number Diff line
@@ -1758,17 +1758,13 @@ static int talk_to_blkback(struct xenbus_device *dev, 
	const char *message = NULL;

	struct xenbus_transaction xbt;

	int err;

	unsigned int i, max_page_order = 0;

	unsigned int ring_page_order = 0;

	unsigned int i, max_page_order;

	unsigned int ring_page_order;



	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "max-ring-page-order", "%u", &max_page_order);

	if (err != 1)

		info->nr_ring_pages = 1;

	else {

	max_page_order = xenbus_read_unsigned(info->xbdev->otherend,

					      "max-ring-page-order", 0);

	ring_page_order = min(xen_blkif_max_ring_order, max_page_order);

	info->nr_ring_pages = 1 << ring_page_order;

	}



	for (i = 0; i < info->nr_rings; i++) {

		struct blkfront_ring_info *rinfo = &info->rinfo[i];
@@ -1877,18 +1873,14 @@ static int talk_to_blkback(struct xenbus_device *dev, 


static int negotiate_mq(struct blkfront_info *info)

{

	unsigned int backend_max_queues = 0;

	int err;

	unsigned int backend_max_queues;

	unsigned int i;



	BUG_ON(info->nr_rings);



	/* Check if backend supports multiple queues. */

	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "multi-queue-max-queues", "%u", &backend_max_queues);

	if (err < 0)

		backend_max_queues = 1;



	backend_max_queues = xenbus_read_unsigned(info->xbdev->otherend,

						  "multi-queue-max-queues", 1);

	info->nr_rings = min(backend_max_queues, xen_blkif_max_queues);

	/* We need at least one ring. */

	if (!info->nr_rings)
@@ -2195,7 +2187,6 @@ static void blkfront_setup_discard(struct blkfront_info *info) 
	int err;

	unsigned int discard_granularity;

	unsigned int discard_alignment;

	unsigned int discard_secure;



	info->feature_discard = 1;

	err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
@@ -2206,10 +2197,9 @@ static void blkfront_setup_discard(struct blkfront_info *info) 
		info->discard_granularity = discard_granularity;

		info->discard_alignment = discard_alignment;

	}

	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "discard-secure", "%u", &discard_secure);

	if (err > 0)

		info->feature_secdiscard = !!discard_secure;

	info->feature_secdiscard =

		!!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure",

				       0);

}



static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
@@ -2301,16 +2291,11 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) 
 */

static void blkfront_gather_backend_features(struct blkfront_info *info)

{

	int err;

	int barrier, flush, discard, persistent;

	unsigned int indirect_segments;



	info->feature_flush = 0;

	info->feature_fua = 0;



	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "feature-barrier", "%d", &barrier);



	/*

	 * If there's no "feature-barrier" defined, then it means

	 * we're dealing with a very old backend which writes
@@ -2318,7 +2303,7 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) 
	 *

	 * If there are barriers, then we use flush.

	 */

	if (err > 0 && barrier) {

	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-barrier", 0)) {

		info->feature_flush = 1;

		info->feature_fua = 1;

	}
@@ -2327,33 +2312,21 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) 
	 * And if there is "feature-flush-cache" use that above

	 * barriers.

	 */

	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "feature-flush-cache", "%d", &flush);



	if (err > 0 && flush) {

	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-flush-cache",

				 0)) {

		info->feature_flush = 1;

		info->feature_fua = 0;

	}



	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "feature-discard", "%d", &discard);



	if (err > 0 && discard)

	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0))

		blkfront_setup_discard(info);



	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "feature-persistent", "%d", &persistent);

	if (err <= 0)

		info->feature_persistent = 0;

	else

		info->feature_persistent = persistent;

	info->feature_persistent =

		xenbus_read_unsigned(info->xbdev->otherend,

				     "feature-persistent", 0);



	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "feature-max-indirect-segments", "%u",

			   &indirect_segments);

	if (err <= 0)

		info->max_indirect_segments = 0;

	else

	indirect_segments = xenbus_read_unsigned(info->xbdev->otherend,

					"feature-max-indirect-segments", 0);

	info->max_indirect_segments = min(indirect_segments,

					  xen_blkif_max_segments);

}
@@ -2420,11 +2393,9 @@ static void blkfront_connect(struct blkfront_info *info) 
	 * provide this. Assume physical sector size to be the same as

	 * sector_size in that case.

	 */

	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,

			   "physical-sector-size", "%u", &physical_sector_size);

	if (err != 1)

		physical_sector_size = sector_size;



	physical_sector_size = xenbus_read_unsigned(info->xbdev->otherend,

						    "physical-sector-size",

						    sector_size);

	blkfront_gather_backend_features(info);

	for (i = 0; i < info->nr_rings; i++) {

		err = blkfront_setup_indirect(&info->rinfo[i]);