Commit 9f4107b0 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: store bdev->bd_disk->fops->submit_bio state in bdev 



We have a long chain of memory dereferencing just to whether or not
this disk has a special submit_bio helper. As that's not necessarily
the common case, add a bd_has_submit_bio state in the bdev to avoid
traversing this memory dependency chain if we don't need to.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3838c406

block/bdev.c

+1 −0
Original line number Diff line number Diff line
@@ -419,6 +419,7 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) 
	bdev->bd_inode = inode;

	bdev->bd_queue = disk->queue;

	bdev->bd_stats = alloc_percpu(struct disk_stats);

	bdev->bd_has_submit_bio = false;

	if (!bdev->bd_stats) {

		iput(inode);

		return NULL;

block/blk-core.c

+4 −4
Original line number Diff line number Diff line
@@ -587,14 +587,14 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q, 


static void __submit_bio(struct bio *bio)

{

	struct gendisk *disk = bio->bi_bdev->bd_disk;



	if (unlikely(!blk_crypto_bio_prep(&bio)))

		return;



	if (!disk->fops->submit_bio) {

	if (!bio->bi_bdev->bd_has_submit_bio) {

		blk_mq_submit_bio(bio);

	} else if (likely(bio_queue_enter(bio) == 0)) {

		struct gendisk *disk = bio->bi_bdev->bd_disk;



		disk->fops->submit_bio(bio);

		blk_queue_exit(disk->queue);

	}
@@ -698,7 +698,7 @@ void submit_bio_noacct_nocheck(struct bio *bio) 
	 */

	if (current->bio_list)

		bio_list_add(&current->bio_list[0], bio);

	else if (!bio->bi_bdev->bd_disk->fops->submit_bio)

	else if (!bio->bi_bdev->bd_has_submit_bio)

		__submit_bio_noacct_mq(bio);

	else

		__submit_bio_noacct(bio);

block/genhd.c

+3 −0
Original line number Diff line number Diff line
@@ -420,6 +420,9 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, 
	 */

	elevator_init_mq(disk->queue);



	/* Mark bdev as having a submit_bio, if needed */

	disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL;



	/*

	 * If the driver provides an explicit major number it also must provide

	 * the number of minors numbers supported, and those will be used to

include/linux/blk_types.h

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ struct block_device { 
	bool			bd_read_only;	/* read-only policy */

	u8			bd_partno;

	bool			bd_write_holder;

	bool			bd_has_submit_bio;

	dev_t			bd_dev;

	atomic_t		bd_openers;

	spinlock_t		bd_size_lock; /* for bd_inode->i_size updates */