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>

3 files changed, 4 insertions, 9 deletions

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 20b4111fa050..c8d087655eff 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -106,10 +106,7 @@ bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
          */
         q->ordseq = 0;
         rq = q->orig_bar_rq;
-
-        if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
-                BUG();
-
+        __blk_end_request_all(rq, q->orderr);
         return true;
 }
 
@@ -252,9 +249,7 @@ bool blk_do_ordered(struct request_queue *q, struct request **rqp)
                          * with prejudice.
                          */
                         elv_dequeue_request(q, rq);
-                        if (__blk_end_request(rq, -EOPNOTSUPP,
-                                              blk_rq_bytes(rq)))
-                                BUG();
+                        __blk_end_request_all(rq, -EOPNOTSUPP);
                         *rqp = NULL;
                         return false;
                 }
diff --git a/block/blk-core.c b/block/blk-core.c
index b84250d3019b..0520cc704585 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1780,7 +1780,7 @@ struct request *elv_next_request(struct request_queue *q)
                         break;
                 } else if (ret == BLKPREP_KILL) {
                         rq->cmd_flags |= REQ_QUIET;
-                        __blk_end_request(rq, -EIO, blk_rq_bytes(rq));
+                        __blk_end_request_all(rq, -EIO);
                 } else {
                         printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
                         break;
diff --git a/block/elevator.c b/block/elevator.c
index b03b8752e18b..1af5d9f04aff 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -810,7 +810,7 @@ void elv_abort_queue(struct request_queue *q)
                 rq = list_entry_rq(q->queue_head.next);
                 rq->cmd_flags |= REQ_QUIET;
                 trace_block_rq_abort(q, rq);
-                __blk_end_request(rq, -EIO, blk_rq_bytes(rq));
+                __blk_end_request_all(rq, -EIO);
         }
 }
 EXPORT_SYMBOL(elv_abort_queue);