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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tejun Heo 2019-08-28 15:05:53 -07:00 committed by Jens Axboe
parent 86a5bba5c2
commit 015d254cb0
2 changed files with 44 additions and 19 deletions
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62
block/blk-cgroup.c
View File

@ -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;
int ret;
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);
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:

1
include/linux/blk-cgroup.h
View File

@ -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);