Commit 015d254c authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep() 



Separate out blkcg_conf_get_disk() so that it can be used by blkcg
policy interface file input parsers before the policy is actually
enabled.  This doesn't introduce any functional changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 86a5bba5

block/blk-cgroup.c

+43 −19
Original line number Diff line number Diff line
@@ -753,6 +753,44 @@ static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg, 
	return __blkg_lookup(blkcg, q, true /* update_hint */);

}



/**

 * blkg_conf_prep - parse and prepare 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

 * 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)

{

	char *input = *inputp;

	unsigned int major, minor;

	struct gendisk *disk;

	int key_len, part;



	if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)

		return ERR_PTR(-EINVAL);



	input += key_len;

	if (!isspace(*input))

		return ERR_PTR(-EINVAL);

	input = skip_spaces(input);



	disk = get_gendisk(MKDEV(major, minor), &part);

	if (!disk)

		return ERR_PTR(-ENODEV);

	if (part) {

		put_disk_and_module(disk);

		return ERR_PTR(-ENODEV);

	}



	*inputp = input;

	return disk;

}



/**

 * blkg_conf_prep - parse and prepare for per-blkg config update

 * @blkcg: target block cgroup
@@ -772,25 +810,11 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, 
	struct gendisk *disk;

	struct request_queue *q;

	struct blkcg_gq *blkg;

	unsigned int major, minor;

	int key_len, part, ret;

	char *body;



	if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)

		return -EINVAL;



	body = input + key_len;

	if (!isspace(*body))

		return -EINVAL;

	body = skip_spaces(body);

	int ret;



	disk = get_gendisk(MKDEV(major, minor), &part);

	if (!disk)

		return -ENODEV;

	if (part) {

		ret = -ENODEV;

		goto fail;

	}

	disk = blkcg_conf_get_disk(&input);

	if (IS_ERR(disk))

		return PTR_ERR(disk);



	q = disk->queue;
@@ -856,7 +880,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, 
success:

	ctx->disk = disk;

	ctx->blkg = blkg;

	ctx->body = body;

	ctx->body = input;

	return 0;



fail_unlock:

include/linux/blk-cgroup.h

+1 −0
Original line number Diff line number Diff line
@@ -234,6 +234,7 @@ struct blkg_conf_ctx { 
	char				*body;

};



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);

void blkg_conf_finish(struct blkg_conf_ctx *ctx);