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| author | Juergen Gross | 2016-10-31 14:58:40 +0100 |
|---|---|---|
| committer | Juergen Gross | 2016-11-07 13:55:07 +0100 |
| commit | 8235777b2068e3280b6fa1413f1940ade31f0adf (patch) | |
| tree | 3a559cc5e59af90987bae75ee234371e33b5742c /drivers/block/xen-blkback/xenbus.c | |
| parent | xen: introduce xenbus_read_unsigned() (diff) | |
| download | kernel-qcow2-linux-8235777b2068e3280b6fa1413f1940ade31f0adf.tar.gz kernel-qcow2-linux-8235777b2068e3280b6fa1413f1940ade31f0adf.tar.xz kernel-qcow2-linux-8235777b2068e3280b6fa1413f1940ade31f0adf.zip | |
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/block/xen-blkback/xenbus.c')
| -rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 36 |
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)) |