block: change ->make_request_fn() and users to return a queue cookie

No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.

Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
diff --git a/drivers/nvdimm/blk.c b/drivers/nvdimm/blk.c
index 0df77cb..91a336e 100644
--- a/drivers/nvdimm/blk.c
+++ b/drivers/nvdimm/blk.c
@@ -161,7 +161,7 @@
 	return err;
 }
 
-static void nd_blk_make_request(struct request_queue *q, struct bio *bio)
+static blk_qc_t nd_blk_make_request(struct request_queue *q, struct bio *bio)
 {
 	struct block_device *bdev = bio->bi_bdev;
 	struct gendisk *disk = bdev->bd_disk;
@@ -208,6 +208,7 @@
 
  out:
 	bio_endio(bio);
+	return BLK_QC_T_NONE;
 }
 
 static int nd_blk_rw_bytes(struct nd_namespace_common *ndns,
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index eae93ab..efb2c1c 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1150,7 +1150,7 @@
 	return ret;
 }
 
-static void btt_make_request(struct request_queue *q, struct bio *bio)
+static blk_qc_t btt_make_request(struct request_queue *q, struct bio *bio)
 {
 	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct btt *btt = q->queuedata;
@@ -1198,6 +1198,7 @@
 
 out:
 	bio_endio(bio);
+	return BLK_QC_T_NONE;
 }
 
 static int btt_rw_page(struct block_device *bdev, sector_t sector,
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 0ba6a97..3963b75 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -64,7 +64,7 @@
 	kunmap_atomic(mem);
 }
 
-static void pmem_make_request(struct request_queue *q, struct bio *bio)
+static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 {
 	bool do_acct;
 	unsigned long start;
@@ -84,6 +84,7 @@
 		wmb_pmem();
 
 	bio_endio(bio);
+	return BLK_QC_T_NONE;
 }
 
 static int pmem_rw_page(struct block_device *bdev, sector_t sector,