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>

1 files changed, 32 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 501f684..e33c835 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -883,6 +883,22 @@ static inline bool blk_end_request(struct request *rq, int error,
 }
 
 /**
+ * blk_end_request_all - Helper function for drives to finish the request.
+ * @rq: the request to finish
+ * @err: %0 for success, < %0 for error
+ *
+ * Description:
+ *     Completely finish @rq.
+ */
+static inline void blk_end_request_all(struct request *rq, int error)
+{
+	bool pending;
+
+	pending = blk_end_request(rq, error, blk_rq_bytes(rq));
+	BUG_ON(pending);
+}
+
+/**
  * __blk_end_request - Helper function for drivers to complete the request.
  * @rq:       the request being processed
  * @error:    %0 for success, < %0 for error
@@ -902,6 +918,22 @@ static inline bool __blk_end_request(struct request *rq, int error,
 }
 
 /**
+ * __blk_end_request_all - Helper function for drives to finish the request.
+ * @rq: the request to finish
+ * @err: %0 for success, < %0 for error
+ *
+ * Description:
+ *     Completely finish @rq.  Must be called with queue lock held.
+ */
+static inline void __blk_end_request_all(struct request *rq, int error)
+{
+	bool pending;
+
+	pending = __blk_end_request(rq, error, blk_rq_bytes(rq));
+	BUG_ON(pending);
+}
+
+/**
  * end_request - end I/O on the current segment of the request
  * @rq:		the request being processed
  * @uptodate:	error value or %0/%1 uptodate flag