block: cleanup rq->data_len usages

With recent unification of fields, it's now guaranteed that
rq->data_len always equals blk_rq_bytes().  Convert all non-IDE direct
users to accessors.  IDE will be converted in a separate patch.

Boaz: spotted incorrect data_len/resid_len conversion in osd.

[ Impact: convert direct rq->data_len usages to blk_rq_bytes() ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 6605ec9..531af9e 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -1927,13 +1927,13 @@
 	/* do we need to support multiple segments? */
 	if (req->bio->bi_vcnt > 1 || rsp->bio->bi_vcnt > 1) {
 		printk("%s: multiple segments req %u %u, rsp %u %u\n",
-		       __func__, req->bio->bi_vcnt, req->data_len,
-		       rsp->bio->bi_vcnt, rsp->data_len);
+		       __func__, req->bio->bi_vcnt, blk_rq_bytes(req),
+		       rsp->bio->bi_vcnt, blk_rq_bytes(rsp));
 		return -EINVAL;
 	}
 
-	ret = smp_execute_task(dev, bio_data(req->bio), req->data_len,
-			       bio_data(rsp->bio), rsp->data_len);
+	ret = smp_execute_task(dev, bio_data(req->bio), blk_rq_bytes(req),
+			       bio_data(rsp->bio), blk_rq_bytes(rsp));
 	if (ret > 0) {
 		/* positive number is the untransferred residual */
 		rsp->resid_len = ret;