xen/blkback: Fix the inhibition to map pages when discarding sector ranges.

The 'operation' parameters are the ones provided to the bio layer while
the req->operation are the ones passed in between the backend and
frontend. We used the wrong 'operation' value to squash the
call to map pages when processing the discard operation resulting
in mapping the pages unnecessarily.

CC: Li Dongyang <lidongyang@novell.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index dde71f72985d38ac1263c2edce8ef3754de99815..ca23dff7d5d1368da2b90365b32bc65f16d9e44a 100644 (file)
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -707,7 +707,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
         * the hypercall to unmap the grants - that is all done in
         * xen_blkbk_unmap.
         */
-       if (operation != BLKIF_OP_DISCARD &&
+       if (operation != REQ_DISCARD &&
                        xen_blkbk_map(req, pending_req, seg))
                goto fail_flush;