From: Tejun Heo tj@kernel.org
mainline inclusion from mainline-5.4-rc1 commit 015d254cb02b6d8eec4b3366274bf4672f9e0b64 category: feature bugzilla: 38688 CVE: NA
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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 Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 e592167449aa3..003965683d0f2 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -801,6 +801,44 @@ 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 @@ -820,25 +858,11 @@ 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;
@@ -904,7 +928,7 @@ 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 5435f97bc0587..911cc20d959a6 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -236,6 +236,7 @@ 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);