diff --git a/block/blk-core.c b/block/blk-core.c
index 3596ca71909b..6226a380fb6d 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -127,7 +127,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	INIT_LIST_HEAD(&rq->timeout_list);
 	rq->cpu = -1;
 	rq->q = q;
-	rq->sector = (sector_t) -1;
+	rq->__sector = (sector_t) -1;
 	INIT_HLIST_NODE(&rq->hash);
 	RB_CLEAR_NODE(&rq->rb_node);
 	rq->cmd = rq->__cmd;
@@ -1095,7 +1095,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
 		req->cmd_flags |= REQ_NOIDLE;
 
 	req->errors = 0;
-	req->sector = bio->bi_sector;
+	req->__sector = bio->bi_sector;
 	req->ioprio = bio_prio(bio);
 	blk_rq_bio_prep(req->q, req, bio);
 }
@@ -1143,7 +1143,7 @@ static int __make_request(struct request_queue *q, struct bio *bio)
 
 		req->biotail->bi_next = bio;
 		req->biotail = bio;
-		req->data_len += bytes;
+		req->__data_len += bytes;
 		req->ioprio = ioprio_best(req->ioprio, prio);
 		if (!blk_rq_cpu_valid(req))
 			req->cpu = bio->bi_comp_cpu;
@@ -1169,8 +1169,8 @@ static int __make_request(struct request_queue *q, struct bio *bio)
 		 * not touch req->buffer either...
 		 */
 		req->buffer = bio_data(bio);
-		req->sector = bio->bi_sector;
-		req->data_len += bytes;
+		req->__sector = bio->bi_sector;
+		req->__data_len += bytes;
 		req->ioprio = ioprio_best(req->ioprio, prio);
 		if (!blk_rq_cpu_valid(req))
 			req->cpu = bio->bi_comp_cpu;
@@ -1878,7 +1878,7 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 		 * can find how many bytes remain in the request
 		 * later.
 		 */
-		req->data_len = 0;
+		req->__data_len = 0;
 		return false;
 	}
 
@@ -1892,12 +1892,12 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 		bio_iovec(bio)->bv_len -= nr_bytes;
 	}
 
-	req->data_len -= total_bytes;
+	req->__data_len -= total_bytes;
 	req->buffer = bio_data(req->bio);
 
 	/* update sector only for requests with clear definition of sector */
 	if (blk_fs_request(req) || blk_discard_rq(req))
-		req->sector += total_bytes >> 9;
+		req->__sector += total_bytes >> 9;
 
 	/*
 	 * If total number of sectors is less than the first segment
@@ -1905,7 +1905,7 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 	 */
 	if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
 		printk(KERN_ERR "blk: request botched\n");
-		req->data_len = blk_rq_cur_bytes(req);
+		req->__data_len = blk_rq_cur_bytes(req);
 	}
 
 	/* recalculate the number of segments */
@@ -2032,7 +2032,7 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 		rq->nr_phys_segments = bio_phys_segments(q, bio);
 		rq->buffer = bio_data(bio);
 	}
-	rq->data_len = bio->bi_size;
+	rq->__data_len = bio->bi_size;
 	rq->bio = rq->biotail = bio;
 
 	if (bio->bi_bdev)
diff --git a/block/blk-map.c b/block/blk-map.c
index 694fefad34e7..56082bea4504 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -20,7 +20,7 @@ int blk_rq_append_bio(struct request_queue *q, struct request *rq,
 		rq->biotail->bi_next = bio;
 		rq->biotail = bio;
 
-		rq->data_len += bio->bi_size;
+		rq->__data_len += bio->bi_size;
 	}
 	return 0;
 }
diff --git a/block/blk-merge.c b/block/blk-merge.c
index b8df66aef0f8..4974dd5767e5 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -370,7 +370,7 @@ static int attempt_merge(struct request_queue *q, struct request *req,
 	req->biotail->bi_next = next->bio;
 	req->biotail = next->biotail;
 
-	req->data_len += blk_rq_bytes(next);
+	req->__data_len += blk_rq_bytes(next);
 
 	elv_merge_requests(q, req, next);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ce2bf5efa9ba..c75580345700 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -166,8 +166,9 @@ struct request {
 	enum rq_cmd_type_bits cmd_type;
 	unsigned long atomic_flags;
 
-	sector_t sector;	/* sector cursor */
-	unsigned int data_len;	/* total data len, don't access directly */
+	/* the following two fields are internal, NEVER access directly */
+	sector_t __sector;		/* sector cursor */
+	unsigned int __data_len;	/* total data len */
 
 	struct bio *bio;
 	struct bio *biotail;
@@ -828,12 +829,12 @@ extern void blkdev_dequeue_request(struct request *req);
  */
 static inline sector_t blk_rq_pos(const struct request *rq)
 {
-	return rq->sector;
+	return rq->__sector;
 }
 
 static inline unsigned int blk_rq_bytes(const struct request *rq)
 {
-	return rq->data_len;
+	return rq->__data_len;
 }
 
 static inline int blk_rq_cur_bytes(const struct request *rq)