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>

2 files changed, 5 insertions, 22 deletions

diff --git a/drivers/cdrom/gdrom.c b/drivers/cdrom/gdrom.c
index 2eecb779437b..fee9a9e83fc9 100644
--- a/drivers/cdrom/gdrom.c
+++ b/drivers/cdrom/gdrom.c
@@ -632,7 +632,7 @@ static void gdrom_readdisk_dma(struct work_struct *work)
                 * before handling ending the request */
                 spin_lock(&gdrom_lock);
                 list_del_init(&req->queuelist);
-                __blk_end_request(req, err, blk_rq_bytes(req));
+                __blk_end_request_all(req, err);
         }
         spin_unlock(&gdrom_lock);
         kfree(read_command);
diff --git a/drivers/cdrom/viocd.c b/drivers/cdrom/viocd.c
index 13929356135c..cc3efa096e1a 100644
--- a/drivers/cdrom/viocd.c
+++ b/drivers/cdrom/viocd.c
@@ -291,23 +291,6 @@ static int send_request(struct request *req)
         return 0;
 }
 
-static void viocd_end_request(struct request *req, int error)
-{
-        int nsectors = req->hard_nr_sectors;
-
-        /*
-         * Make sure it's fully ended, and ensure that we process
-         * at least one sector.
-         */
-        if (blk_pc_request(req))
-                nsectors = (req->data_len + 511) >> 9;
-        if (!nsectors)
-                nsectors = 1;
-
-        if (__blk_end_request(req, error, nsectors << 9))
-                BUG();
-}
-
 static int rwreq;
 
 static void do_viocd_request(struct request_queue *q)
@@ -316,11 +299,11 @@ static void do_viocd_request(struct request_queue *q)
 
         while ((rwreq == 0) && ((req = elv_next_request(q)) != NULL)) {
                 if (!blk_fs_request(req))
-                        viocd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                 else if (send_request(req) < 0) {
                         printk(VIOCD_KERN_WARNING
                                         "unable to send message to OS/400!");
-                        viocd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                 } else
                         rwreq++;
         }
@@ -531,9 +514,9 @@ return_complete:
                                         "with rc %d:0x%04X: %s\n",
                                         req, event->xRc,
                                         bevent->sub_result, err->msg);
-                        viocd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                 } else
-                        viocd_end_request(req, 0);
+                        __blk_end_request_all(req, 0);
 
                 /* restart handling of incoming requests */
                 spin_unlock_irqrestore(&viocd_reqlock, flags);