xen/blkback: Squash the discard support for 'file' and 'phy' type.

The only reason for the distinction was for the special case of
'file' (which is assumed to be loopback device), was to reach inside
the loopback device, find the underlaying file, and call fallocate on it.
Fortunately "xen-blkback: convert hole punching to discard request on
loop devices" removes that use-case and we now based the discard
support based on blk_queue_discard(q) and extract all appropriate
parameters from the 'struct request_queue'.

CC: Li Dongyang <lidongyang@novell.com>
Acked-by: Jan Beulich <JBeulich@suse.com>
[v1: Dropping pointless initializer and keeping blank line]
[v2: Remove the kfree as it is not used anymore]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 8 insertions, 11 deletions

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 70caa8969972..73f196ca713f 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -398,21 +398,18 @@ static int dispatch_discard_io(struct xen_blkif *blkif,
         int err = 0;
         int status = BLKIF_RSP_OKAY;
         struct block_device *bdev = blkif->vbd.bdev;
+        unsigned long secure;
 
         blkif->st_ds_req++;
 
         xen_blkif_get(blkif);
-        if (blkif->blk_backend_type == BLKIF_BACKEND_PHY ||
-            blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
-                unsigned long secure = (blkif->vbd.discard_secure &&
-                        (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
-                        BLKDEV_DISCARD_SECURE : 0;
-                err = blkdev_issue_discard(bdev,
-                                req->u.discard.sector_number,
-                                req->u.discard.nr_sectors,
-                                GFP_KERNEL, secure);
-        } else
-                err = -EOPNOTSUPP;
+        secure = (blkif->vbd.discard_secure &&
+                 (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
+                 BLKDEV_DISCARD_SECURE : 0;
+
+        err = blkdev_issue_discard(bdev, req->u.discard.sector_number,
+                                   req->u.discard.nr_sectors,
+                                   GFP_KERNEL, secure);
 
         if (err == -EOPNOTSUPP) {
                 pr_debug(DRV_PFX "discard op failed, not supported\n");