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authorJuergen Gross <jgross@suse.com>2016-10-31 16:58:40 +0300
committerJuergen Gross <jgross@suse.com>2016-11-07 15:55:07 +0300
commit8235777b2068e3280b6fa1413f1940ade31f0adf (patch)
tree3a559cc5e59af90987bae75ee234371e33b5742c /drivers
parent9c53a1792a5e6c708897d0cb17f2a4509e499a52 (diff)
downloadlinux-8235777b2068e3280b6fa1413f1940ade31f0adf.tar.xz
xen: make use of xenbus_read_unsigned() in xen-blkback
Use xenbus_read_unsigned() instead of xenbus_scanf() when possible. This requires to change the type of one read from int to unsigned, but this case has been wrong before: negative values are not allowed for the modified case. Cc: konrad.wilk@oracle.com Cc: roger.pau@citrix.com Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/xen-blkback/xenbus.c36
1 files changed, 14 insertions, 22 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 3cc6d1d86f1e..415e79b69d34 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -533,13 +533,11 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info
struct xenbus_device *dev = be->dev;
struct xen_blkif *blkif = be->blkif;
int err;
- int state = 0, discard_enable;
+ int state = 0;
struct block_device *bdev = be->blkif->vbd.bdev;
struct request_queue *q = bdev_get_queue(bdev);
- err = xenbus_scanf(XBT_NIL, dev->nodename, "discard-enable", "%d",
- &discard_enable);
- if (err == 1 && !discard_enable)
+ if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1))
return;
if (blk_queue_discard(q)) {
@@ -1039,30 +1037,24 @@ static int connect_ring(struct backend_info *be)
xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
return -ENOSYS;
}
- err = xenbus_scanf(XBT_NIL, dev->otherend,
- "feature-persistent", "%u", &pers_grants);
- if (err <= 0)
- pers_grants = 0;
-
+ pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
+ 0);
be->blkif->vbd.feature_gnt_persistent = pers_grants;
be->blkif->vbd.overflow_max_grants = 0;
/*
* Read the number of hardware queues from frontend.
*/
- err = xenbus_scanf(XBT_NIL, dev->otherend, "multi-queue-num-queues",
- "%u", &requested_num_queues);
- if (err < 0) {
- requested_num_queues = 1;
- } else {
- if (requested_num_queues > xenblk_max_queues
- || requested_num_queues == 0) {
- /* Buggy or malicious guest. */
- xenbus_dev_fatal(dev, err,
- "guest requested %u queues, exceeding the maximum of %u.",
- requested_num_queues, xenblk_max_queues);
- return -ENOSYS;
- }
+ requested_num_queues = xenbus_read_unsigned(dev->otherend,
+ "multi-queue-num-queues",
+ 1);
+ if (requested_num_queues > xenblk_max_queues
+ || requested_num_queues == 0) {
+ /* Buggy or malicious guest. */
+ xenbus_dev_fatal(dev, err,
+ "guest requested %u queues, exceeding the maximum of %u.",
+ requested_num_queues, xenblk_max_queues);
+ return -ENOSYS;
}
be->blkif->nr_rings = requested_num_queues;
if (xen_blkif_alloc_rings(be->blkif))