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>
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 5fa9a74..fc71e61 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -146,7 +146,7 @@
 	iv = bip->bip_vec + bip->bip_vcnt;
 
 	if (bip->bip_vcnt &&
-	    bvec_gap_to_prev(bdev_get_queue(bio->bi_bdev),
+	    bvec_gap_to_prev(bio->bi_disk->queue,
 			     &bip->bip_vec[bip->bip_vcnt - 1], offset))
 		return 0;
 
@@ -190,7 +190,7 @@
 static blk_status_t bio_integrity_process(struct bio *bio,
 		struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
 {
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	struct blk_integrity_iter iter;
 	struct bvec_iter bviter;
 	struct bio_vec bv;
@@ -199,7 +199,7 @@
 	void *prot_buf = page_address(bip->bip_vec->bv_page) +
 		bip->bip_vec->bv_offset;
 
-	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
+	iter.disk_name = bio->bi_disk->disk_name;
 	iter.interval = 1 << bi->interval_exp;
 	iter.seed = proc_iter->bi_sector;
 	iter.prot_buf = prot_buf;
@@ -236,8 +236,8 @@
 bool bio_integrity_prep(struct bio *bio)
 {
 	struct bio_integrity_payload *bip;
-	struct blk_integrity *bi;
-	struct request_queue *q;
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
+	struct request_queue *q = bio->bi_disk->queue;
 	void *buf;
 	unsigned long start, end;
 	unsigned int len, nr_pages;
@@ -245,11 +245,9 @@
 	unsigned int intervals;
 	blk_status_t status;
 
-	bi = bdev_get_integrity(bio->bi_bdev);
 	if (!bi)
 		return true;
 
-	q = bdev_get_queue(bio->bi_bdev);
 	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
 		return true;
 
@@ -354,7 +352,7 @@
 	struct bio_integrity_payload *bip =
 		container_of(work, struct bio_integrity_payload, bip_work);
 	struct bio *bio = bip->bip_bio;
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	struct bvec_iter iter = bio->bi_iter;
 
 	/*
@@ -411,7 +409,7 @@
 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 {
 	struct bio_integrity_payload *bip = bio_integrity(bio);
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
 
 	bip->bip_iter.bi_sector += bytes_done >> 9;
@@ -428,7 +426,7 @@
 void bio_integrity_trim(struct bio *bio)
 {
 	struct bio_integrity_payload *bip = bio_integrity(bio);
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 
 	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
 }