From 015d254cb02b6d8eec4b3366274bf4672f9e0b64 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 28 Aug 2019 15:05:53 -0700 Subject: [PATCH] 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 Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 62 ++++++++++++++++++++++++++------------ include/linux/blk-cgroup.h | 1 + 2 files changed, 44 insertions(+), 19 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 78ccbdcfe723..0e2619c1a422 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -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: diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 261248e88eb1..bed9e43f9426 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -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); -- 2.30.2