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>

drivers/scsi/osd/osd_initiator.c

@@ -1299,7 +1299,7 @@ int osd_finalize_request(struct osd_request *or,
 			return ret;
 		}
 		OSD_DEBUG("out bytes=%llu (bytes_req=%u)\n",
-			_LLU(or->out.total_bytes), or->out.req->data_len);
+			_LLU(or->out.total_bytes), blk_rq_bytes(or->out.req));
 	}
 	if (or->in.bio) {
 		ret = blk_rq_append_bio(or->request->q, or->in.req, or->in.bio);
@@ -1308,7 +1308,7 @@ int osd_finalize_request(struct osd_request *or,
 			return ret;
 		}
 		OSD_DEBUG("in bytes=%llu (bytes_req=%u)\n",
-			_LLU(or->in.total_bytes), or->in.req->data_len);
+			_LLU(or->in.total_bytes), blk_rq_bytes(or->in.req));
 	}
 
 	or->out.pad_buff = sg_out_pad_buffer;