block: implement and use [__]blk_end_request_all()

There are many [__]blk_end_request() call sites which call it with
full request length and expect full completion.  Many of them ensure
that the request actually completes by doing BUG_ON() the return
value, which is awkward and error-prone.

This patch adds [__]blk_end_request_all() which takes @rq and @error
and fully completes the request.  BUG_ON() is added to to ensure that
this actually happens.

Most conversions are simple but there are a few noteworthy ones.

* cdrom/viocd: viocd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/block/dasd: dasd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/char/tape_block: tapeblock_end_request() replaced with direct
  calls to blk_end_request_all().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>

4 files changed, 4 insertions, 8 deletions

diff --git a/drivers/block/cpqarray.c b/drivers/block/cpqarray.c
index ca268ca11159..488a8f4a60aa 100644
--- a/drivers/block/cpqarray.c
+++ b/drivers/block/cpqarray.c
@@ -1024,8 +1024,7 @@ static inline void complete_command(cmdlist_t *cmd, int timeout)
                                 cmd->req.sg[i].size, ddir);
 
         DBGPX(printk("Done with %p\n", rq););
-        if (__blk_end_request(rq, error, blk_rq_bytes(rq)))
-                BUG();
+        __blk_end_request_all(rq, error);
 }
 
 /*
diff --git a/drivers/block/sx8.c b/drivers/block/sx8.c
index ff0448e4bf03..60e85bb6f790 100644
--- a/drivers/block/sx8.c
+++ b/drivers/block/sx8.c
@@ -749,8 +749,7 @@ static inline void carm_end_request_queued(struct carm_host *host,
         struct request *req = crq->rq;
         int rc;
 
-        rc = __blk_end_request(req, error, blk_rq_bytes(req));
-        assert(rc == 0);
+        __blk_end_request_all(req, error);
 
         rc = carm_put_request(host, crq);
         assert(rc == 0);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 5d34764c8a87..50745e64414e 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -62,7 +62,7 @@ static void blk_done(struct virtqueue *vq)
                         break;
                 }
 
-                __blk_end_request(vbr->req, error, blk_rq_bytes(vbr->req));
+                __blk_end_request_all(vbr->req, error);
                 list_del(&vbr->list);
                 mempool_free(vbr, vblk->pool);
         }
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8f905089b72b..cd6cfe3b51e1 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -551,7 +551,6 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 
         for (i = info->ring.rsp_cons; i != rp; i++) {
                 unsigned long id;
-                int ret;
 
                 bret = RING_GET_RESPONSE(&info->ring, i);
                 id   = bret->id;
@@ -578,8 +577,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
                                 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
                                         "request: %x\n", bret->status);
 
-                        ret = __blk_end_request(req, error, blk_rq_bytes(req));
-                        BUG_ON(ret);
+                        __blk_end_request_all(req, error);
                         break;
                 default:
                         BUG();