block: move ->bio_split to the gendisk

Only non-passthrough requests are split by the block layer and use the
->bio_split bio_set.  Move it from the request_queue to the gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220727162300.3089193-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/blk-core.c

@@ -377,7 +377,6 @@ static void blk_timeout_work(struct work_struct *work)
 struct request_queue *blk_alloc_queue(int node_id, bool alloc_srcu)
 {
 	struct request_queue *q;
-	int ret;
 
 	q = kmem_cache_alloc_node(blk_get_queue_kmem_cache(alloc_srcu),
 			GFP_KERNEL | __GFP_ZERO, node_id);
@@ -396,13 +395,9 @@ struct request_queue *blk_alloc_queue(int node_id, bool alloc_srcu)
 	if (q->id < 0)
 		goto fail_srcu;
 
-	ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, 0);
-	if (ret)
-		goto fail_id;
-
 	q->stats = blk_alloc_queue_stats();
 	if (!q->stats)
-		goto fail_split;
+		goto fail_id;
 
 	q->node = node_id;
 
@@ -439,8 +434,6 @@ struct request_queue *blk_alloc_queue(int node_id, bool alloc_srcu)
 
 fail_stats:
 	blk_free_queue_stats(q->stats);
-fail_split:
-	bioset_exit(&q->bio_split);
 fail_id:
 	ida_free(&blk_queue_ida, q->id);
 fail_srcu:

block/blk-merge.c

@@ -331,18 +331,19 @@ static struct bio *bio_split_rw(struct bio *bio, struct request_queue *q,
 struct bio *__bio_split_to_limits(struct bio *bio, struct request_queue *q,
 		       unsigned int *nr_segs)
 {
+	struct bio_set *bs = &bio->bi_bdev->bd_disk->bio_split;
 	struct bio *split;
 
 	switch (bio_op(bio)) {
 	case REQ_OP_DISCARD:
 	case REQ_OP_SECURE_ERASE:
-		split = bio_split_discard(bio, q, nr_segs, &q->bio_split);
+		split = bio_split_discard(bio, q, nr_segs, bs);
 		break;
 	case REQ_OP_WRITE_ZEROES:
-		split = bio_split_write_zeroes(bio, q, nr_segs, &q->bio_split);
+		split = bio_split_write_zeroes(bio, q, nr_segs, bs);
 		break;
 	default:
-		split = bio_split_rw(bio, q, nr_segs, &q->bio_split);
+		split = bio_split_rw(bio, q, nr_segs, bs);
 		break;
 	}
 

block/blk-sysfs.c

@@ -779,8 +779,6 @@ static void blk_release_queue(struct kobject *kobj)
 	if (queue_is_mq(q))
 		blk_mq_release(q);
 
-	bioset_exit(&q->bio_split);
-
 	if (blk_queue_has_srcu(q))
 		cleanup_srcu_struct(q->srcu);
 

block/genhd.c

@@ -1151,6 +1151,7 @@ static void disk_release(struct device *dev)
 		blk_mq_exit_queue(disk->queue);
 
 	blkcg_exit_queue(disk->queue);
+	bioset_exit(&disk->bio_split);
 
 	disk_release_events(disk);
 	kfree(disk->random);
@@ -1342,9 +1343,12 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 	if (!disk)
 		goto out_put_queue;
 
+	if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0))
+		goto out_free_disk;
+
 	disk->bdi = bdi_alloc(node_id);
 	if (!disk->bdi)
-		goto out_free_disk;
+		goto out_free_bioset;
 
 	/* bdev_alloc() might need the queue, set before the first call */
 	disk->queue = q;
@@ -1382,6 +1386,8 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 	iput(disk->part0->bd_inode);
 out_free_bdi:
 	bdi_put(disk->bdi);
+out_free_bioset:
+	bioset_exit(&disk->bio_split);
 out_free_disk:
 	kfree(disk);
 out_put_queue:

drivers/md/dm.c

@@ -1016,7 +1016,7 @@ static void dm_wq_requeue_work(struct work_struct *work)
 	while (io) {
 		struct dm_io *next = io->next;
 
-		dm_io_rewind(io, &md->queue->bio_split);
+		dm_io_rewind(io, &md->disk->bio_split);
 
 		io->next = NULL;
 		__dm_io_complete(io, false);

include/linux/blkdev.h

@@ -140,6 +140,8 @@ struct gendisk {
 	struct request_queue *queue;
 	void *private_data;
 
+	struct bio_set bio_split;
+
 	int flags;
 	unsigned long state;
 #define GD_NEED_PART_SCAN		0
@@ -531,7 +533,6 @@ struct request_queue {
 
 	struct blk_mq_tag_set	*tag_set;
 	struct list_head	tag_set_list;
-	struct bio_set		bio_split;
 
 	struct dentry		*debugfs_dir;
 	struct dentry		*sched_debugfs_dir;