From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 03/10] blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep() Date: Wed, 10 Jul 2019 13:51:21 -0700 Message-ID: <20190710205128.1316483-4-tj@kernel.org> References: <20190710205128.1316483-1-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=NSsXuJroaDqOlhMryi+iSYceW4KouvHH84idtExmGM0=; b=NuEfAEexdKe5z2kFDQNehIrB3aMB/hR+imA+acy7jtmdbjM2moXZf9UjPyRMqFUn7s PeGzkykFUiy3lBsdvRk03i9+xNY1FZYnYDeuNgzAKrK7T4dXIVOuZCtGobmHPS8S1Ge9 +8zzZEyqPNhZw7ml2Q3Hce8U/K5GD0YpG1eHNZGgueLEDIscaK1MIsdGYPK4GlalISdb MU+p4BMnlTYl33MBfDtIFmE5kvqgZt69reT1+uqiOwpBDpKCnkP9dXCnBYcIrAqCglSN pINjO8k4G1kK9ovCBSXNPzb0+xAi9KSYMwvKPojE8DThJSFVAhUrLpt2tCchqcS9tiTX ZsQw== In-Reply-To: <20190710205128.1316483-1-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: axboe@kernel.dk, newella@fb.com, clm@fb.com, josef@toxicpanda.com, dennisz@fb.com, lizefan@huawei.com, hannes@cmpxchg.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, linux-block@vger.kernel.org, cgroups@vger.kernel.org, Tejun Heo 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 --- 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 818e50b4cc7a..aed46a2c553e 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 930631cad5cf..b0eacec11037 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -233,6 +233,7 @@ 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); -- 2.17.1