From 22ae8ce8b89241c94ac00c237752c0ffa37ba5ae Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 26 Nov 2020 09:23:26 +0100 Subject: block: simplify bdev/disk lookup in blkdev_get To simplify block device lookup and a few other upcoming areas, make sure that we always have a struct block_device available for each disk and each partition, and only find existing block devices in bdget. The only downside of this is that each device and partition uses a little more memory. The upside will be that a lot of code can be simplified. With that all we need to look up the block device is to lookup the inode and do a few sanity checks on the gendisk, instead of the separate lookup for the gendisk. For blk-cgroup which wants to access a gendisk without opening it, a new blkdev_{get,put}_no_open low-level interface is added to replace the previous get_gendisk use. Note that the change to look up block device directly instead of the two step lookup using struct gendisk causes a subtile change in behavior: accessing a non-existing partition on an existing block device can now cause a call to request_module. That call is harmless, and in practice no recent system will access these nodes as they aren't created by udev and static /dev/ setups are unusual. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) (limited to 'block/blk-cgroup.c') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c68bdf58c9a6..ad02289a4f7f 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -556,22 +556,22 @@ static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg, } /** - * blkg_conf_prep - parse and prepare for per-blkg config update + * blkcg_conf_open_bdev - parse and open bdev for per-blkg config update * @inputp: input string pointer * * Parse the device node prefix part, MAJ:MIN, of per-blkg config update - * from @input and get and return the matching gendisk. *@inputp is + * from @input and get and return the matching bdev. *@inputp is * updated to point past the device node prefix. Returns an ERR_PTR() * value on error. * * Use this function iff blkg_conf_prep() can't be used for some reason. */ -struct gendisk *blkcg_conf_get_disk(char **inputp) +struct block_device *blkcg_conf_open_bdev(char **inputp) { char *input = *inputp; unsigned int major, minor; - struct gendisk *disk; - int key_len, part; + struct block_device *bdev; + int key_len; if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2) return ERR_PTR(-EINVAL); @@ -581,16 +581,16 @@ struct gendisk *blkcg_conf_get_disk(char **inputp) return ERR_PTR(-EINVAL); input = skip_spaces(input); - disk = get_gendisk(MKDEV(major, minor), &part); - if (!disk) + bdev = blkdev_get_no_open(MKDEV(major, minor)); + if (!bdev) return ERR_PTR(-ENODEV); - if (part) { - put_disk_and_module(disk); + if (bdev_is_partition(bdev)) { + blkdev_put_no_open(bdev); return ERR_PTR(-ENODEV); } *inputp = input; - return disk; + return bdev; } /** @@ -607,18 +607,18 @@ struct gendisk *blkcg_conf_get_disk(char **inputp) */ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, char *input, struct blkg_conf_ctx *ctx) - __acquires(rcu) __acquires(&disk->queue->queue_lock) + __acquires(rcu) __acquires(&bdev->bd_disk->queue->queue_lock) { - struct gendisk *disk; + struct block_device *bdev; struct request_queue *q; struct blkcg_gq *blkg; int ret; - disk = blkcg_conf_get_disk(&input); - if (IS_ERR(disk)) - return PTR_ERR(disk); + bdev = blkcg_conf_open_bdev(&input); + if (IS_ERR(bdev)) + return PTR_ERR(bdev); - q = disk->queue; + q = bdev->bd_disk->queue; rcu_read_lock(); spin_lock_irq(&q->queue_lock); @@ -689,7 +689,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, goto success; } success: - ctx->disk = disk; + ctx->bdev = bdev; ctx->blkg = blkg; ctx->body = input; return 0; @@ -700,7 +700,7 @@ fail_unlock: spin_unlock_irq(&q->queue_lock); rcu_read_unlock(); fail: - put_disk_and_module(disk); + blkdev_put_no_open(bdev); /* * If queue was bypassing, we should retry. Do so after a * short msleep(). It isn't strictly necessary but queue @@ -723,11 +723,11 @@ EXPORT_SYMBOL_GPL(blkg_conf_prep); * with blkg_conf_prep(). */ void blkg_conf_finish(struct blkg_conf_ctx *ctx) - __releases(&ctx->disk->queue->queue_lock) __releases(rcu) + __releases(&ctx->bdev->bd_disk->queue->queue_lock) __releases(rcu) { - spin_unlock_irq(&ctx->disk->queue->queue_lock); + spin_unlock_irq(&ctx->bdev->bd_disk->queue->queue_lock); rcu_read_unlock(); - put_disk_and_module(ctx->disk); + blkdev_put_no_open(ctx->bdev); } EXPORT_SYMBOL_GPL(blkg_conf_finish); -- cgit v1.2.3