nvme: Cleanup and rename nvme_block_nr()

Rename nvme_block_nr() to nvme_sect_to_lba() and use SECTOR_SHIFT
instead of its hard coded value 9. Also add a comment to decribe this
helper.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/core.c

@@ -589,7 +589,7 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 	}
 
 	__rq_for_each_bio(bio, req) {
-		u64 slba = nvme_block_nr(ns, bio->bi_iter.bi_sector);
+		u64 slba = nvme_sect_to_lba(ns, bio->bi_iter.bi_sector);
 		u32 nlb = bio->bi_iter.bi_size >> ns->lba_shift;
 
 		if (n < segments) {
@@ -630,7 +630,7 @@ static inline blk_status_t nvme_setup_write_zeroes(struct nvme_ns *ns,
 	cmnd->write_zeroes.opcode = nvme_cmd_write_zeroes;
 	cmnd->write_zeroes.nsid = cpu_to_le32(ns->head->ns_id);
 	cmnd->write_zeroes.slba =
-		cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
+		cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
 	cmnd->write_zeroes.length =
 		cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
 	cmnd->write_zeroes.control = 0;
@@ -654,7 +654,7 @@ static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
 
 	cmnd->rw.opcode = (rq_data_dir(req) ? nvme_cmd_write : nvme_cmd_read);
 	cmnd->rw.nsid = cpu_to_le32(ns->head->ns_id);
-	cmnd->rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
+	cmnd->rw.slba = cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
 	cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
 
 	if (req_op(req) == REQ_OP_WRITE && ctrl->nr_streams)

drivers/nvme/host/nvme.h

@@ -418,9 +418,12 @@ static inline int nvme_reset_subsystem(struct nvme_ctrl *ctrl)
 	return ctrl->ops->reg_write32(ctrl, NVME_REG_NSSR, 0x4E564D65);
 }
 
-static inline u64 nvme_block_nr(struct nvme_ns *ns, sector_t sector)
+/*
+ * Convert a 512B sector number to a device logical block number.
+ */
+static inline u64 nvme_sect_to_lba(struct nvme_ns *ns, sector_t sector)
 {
-	return (sector >> (ns->lba_shift - 9));
+	return sector >> (ns->lba_shift - SECTOR_SHIFT);
 }
 
 static inline void nvme_end_request(struct request *req, __le16 status,