block: replace bi_bdev with a gendisk pointer and partitions index

This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 7 insertions, 25 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index c49f1f8..f03452d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -613,11 +613,7 @@ int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
 
 		if (!disk)
 			goto submit;
-		bio->bi_bdev = bdget_disk(disk, 0);
-		if (!bio->bi_bdev) {
-			ret = -ENODEV;
-			goto out_unmap;
-		}
+		bio->bi_disk = disk;
 
 		if (meta_buffer && meta_len) {
 			struct bio_integrity_payload *bip;
@@ -668,11 +664,8 @@ int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
  out_free_meta:
 	kfree(meta);
  out_unmap:
-	if (bio) {
-		if (disk && bio->bi_bdev)
-			bdput(bio->bi_bdev);
+	if (bio)
 		blk_rq_unmap_user(bio);
-	}
  out:
 	blk_mq_free_request(req);
 	return ret;
diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index be85413..c1a2856 100644
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -643,17 +643,9 @@ static int nvme_nvm_submit_user_cmd(struct request_queue *q,
 			vcmd->ph_rw.metadata = cpu_to_le64(metadata_dma);
 		}
 
-		if (!disk)
-			goto submit;
-
-		bio->bi_bdev = bdget_disk(disk, 0);
-		if (!bio->bi_bdev) {
-			ret = -ENODEV;
-			goto err_meta;
-		}
+		bio->bi_disk = disk;
 	}
 
-submit:
 	blk_execute_rq(q, NULL, rq, 0);
 
 	if (nvme_req(rq)->flags & NVME_REQ_CANCELLED)
@@ -673,11 +665,8 @@ err_meta:
 	if (meta_buf && meta_len)
 		dma_pool_free(dev->dma_pool, metadata, metadata_dma);
 err_map:
-	if (bio) {
-		if (disk && bio->bi_bdev)
-			bdput(bio->bi_bdev);
+	if (bio)
 		blk_rq_unmap_user(bio);
-	}
 err_ppa:
 	if (ppa_buf && ppa_len)
 		dma_pool_free(dev->dma_pool, ppa_list, ppa_dma);
diff --git a/drivers/nvme/target/io-cmd.c b/drivers/nvme/target/io-cmd.c
index 3b4d47a..0d4c23d 100644
--- a/drivers/nvme/target/io-cmd.c
+++ b/drivers/nvme/target/io-cmd.c
@@ -68,7 +68,7 @@ static void nvmet_execute_rw(struct nvmet_req *req)
 
 	nvmet_inline_bio_init(req);
 	bio = &req->inline_bio;
-	bio->bi_bdev = req->ns->bdev;
+	bio_set_dev(bio, req->ns->bdev);
 	bio->bi_iter.bi_sector = sector;
 	bio->bi_private = req;
 	bio->bi_end_io = nvmet_bio_done;
@@ -80,7 +80,7 @@ static void nvmet_execute_rw(struct nvmet_req *req)
 			struct bio *prev = bio;
 
 			bio = bio_alloc(GFP_KERNEL, min(sg_cnt, BIO_MAX_PAGES));
-			bio->bi_bdev = req->ns->bdev;
+			bio_set_dev(bio, req->ns->bdev);
 			bio->bi_iter.bi_sector = sector;
 			bio_set_op_attrs(bio, op, op_flags);
 
@@ -104,7 +104,7 @@ static void nvmet_execute_flush(struct nvmet_req *req)
 	nvmet_inline_bio_init(req);
 	bio = &req->inline_bio;
 
-	bio->bi_bdev = req->ns->bdev;
+	bio_set_dev(bio, req->ns->bdev);
 	bio->bi_private = req;
 	bio->bi_end_io = nvmet_bio_done;
 	bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;