blk_end_request: add/export functions to get request size (take 4)

This patch adds/exports functions to get the size of request in bytes.
They are useful because blk_end_request interfaces take bytes
as a completed I/O size instead of sectors.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block/ll_rw_blk.c

@@ -3723,13 +3723,32 @@ static inline void __end_request(struct request *rq, int uptodate,
 	}
 }
 
-static unsigned int rq_byte_size(struct request *rq)
+/**
+ * blk_rq_bytes - Returns bytes left to complete in the entire request
+ **/
+unsigned int blk_rq_bytes(struct request *rq)
 {
 	if (blk_fs_request(rq))
 		return rq->hard_nr_sectors << 9;
 
 	return rq->data_len;
 }
+EXPORT_SYMBOL_GPL(blk_rq_bytes);
+
+/**
+ * blk_rq_cur_bytes - Returns bytes left to complete in the current segment
+ **/
+unsigned int blk_rq_cur_bytes(struct request *rq)
+{
+	if (blk_fs_request(rq))
+		return rq->current_nr_sectors << 9;
+
+	if (rq->bio)
+		return rq->bio->bi_size;
+
+	return rq->data_len;
+}
+EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
 
 /**
  * end_queued_request - end all I/O on a queued request
@@ -3744,7 +3763,7 @@ static unsigned int rq_byte_size(struct request *rq)
  **/
 void end_queued_request(struct request *rq, int uptodate)
 {
-	__end_request(rq, uptodate, rq_byte_size(rq), 1);
+	__end_request(rq, uptodate, blk_rq_bytes(rq), 1);
 }
 EXPORT_SYMBOL(end_queued_request);
 
@@ -3761,7 +3780,7 @@ EXPORT_SYMBOL(end_queued_request);
  **/
 void end_dequeued_request(struct request *rq, int uptodate)
 {
-	__end_request(rq, uptodate, rq_byte_size(rq), 0);
+	__end_request(rq, uptodate, blk_rq_bytes(rq), 0);
 }
 EXPORT_SYMBOL(end_dequeued_request);
 

include/linux/blkdev.h

@@ -736,6 +736,14 @@ extern void end_queued_request(struct request *, int);
 extern void end_dequeued_request(struct request *, int);
 extern void blk_complete_request(struct request *);
 
+/*
+ * blk_end_request() takes bytes instead of sectors as a complete size.
+ * blk_rq_bytes() returns bytes left to complete in the entire request.
+ * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
+ */
+extern unsigned int blk_rq_bytes(struct request *rq);
+extern unsigned int blk_rq_cur_bytes(struct request *rq);
+
 /*
  * end_that_request_first/chunk() takes an uptodate argument. we account
  * any value <= as an io error. 0 means -EIO for compatability reasons,