block: implement blk_rq_pos/[cur_]sectors() and convert obvious ones

Implement accessors - blk_rq_pos(), blk_rq_sectors() and
blk_rq_cur_sectors() which return rq->hard_sector, rq->hard_nr_sectors
and rq->hard_cur_sectors respectively and convert direct references of
the said fields to the accessors.

This is in preparation of request data length handling cleanup.

Geert	: suggested adding const to struct request * parameter to accessors
Sergei	: spotted error in patch description

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Ackec-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/xsysace.c b/drivers/block/xsysace.c
index b1e1d7e..5722931 100644
--- a/drivers/block/xsysace.c
+++ b/drivers/block/xsysace.c
@@ -645,8 +645,8 @@
 
 		/* Okay, it's a data request, set it up for transfer */
 		dev_dbg(ace->dev,
-			"request: sec=%llx hcnt=%lx, ccnt=%x, dir=%i\n",
-			(unsigned long long) req->sector, req->hard_nr_sectors,
+			"request: sec=%llx hcnt=%x, ccnt=%x, dir=%i\n",
+			(unsigned long long) req->sector, blk_rq_sectors(req),
 			req->current_nr_sectors, rq_data_dir(req));
 
 		ace->req = req;
@@ -654,7 +654,7 @@
 		ace->data_count = req->current_nr_sectors * ACE_BUF_PER_SECTOR;
 		ace_out32(ace, ACE_MPULBA, req->sector & 0x0FFFFFFF);
 
-		count = req->hard_nr_sectors;
+		count = blk_rq_sectors(req);
 		if (rq_data_dir(req)) {
 			/* Kick off write request */
 			dev_dbg(ace->dev, "write data\n");
@@ -719,8 +719,8 @@
 		/* bio finished; is there another one? */
 		if (__blk_end_request(ace->req, 0,
 					blk_rq_cur_bytes(ace->req))) {
-			/* dev_dbg(ace->dev, "next block; h=%li c=%i\n",
-			 *      ace->req->hard_nr_sectors,
+			/* dev_dbg(ace->dev, "next block; h=%u c=%u\n",
+			 *      blk_rq_sectors(ace->req),
 			 *      ace->req->current_nr_sectors);
 			 */
 			ace->data_ptr = ace->req->buffer;