From 36aa9e5f591e84d67aad2c5bff75e413d77660dd Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 14:55:31 -0700 Subject: [PATCH] blkcg: move body parsing from blkg_conf_prep() to its callers Currently, blkg_conf_prep() expects input to be of the following form MAJ:MIN NUM and reads the NUM part into blkg_conf_ctx->v. This is quite restrictive and gets in the way in implementing blkcg interface for the unified hierarchy. This patch updates blkg_conf_prep() so that it expects MAJ:MIN BODY_STR where BODY_STR is an arbitrary string. blkg_conf_ctx->v is replaced with ->body which is a char pointer pointing to the start of BODY_STR. Parsing of the body is moved to blkg_conf_prep()'s callers. To allow using, for example, strsep() on blkg_conf_ctx->val, it is a non-const pointer and to accommodate that const is dropped from @input too. This doesn't cause any behavior changes. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 22 ++++++++++++++-------- block/blk-throttle.c | 18 ++++++++++++------ block/cfq-iosched.c | 17 +++++++++++------ include/linux/blk-cgroup.h | 4 ++-- 4 files changed, 39 insertions(+), 22 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 429726bed560..8ee1ca4d4f2f 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include "blk.h" @@ -773,23 +774,28 @@ EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum); * @ctx: blkg_conf_ctx to be filled * * Parse per-blkg config update from @input and initialize @ctx with the - * result. @ctx->blkg points to the blkg to be updated and @ctx->v the new - * value. This function returns with RCU read lock and queue lock held and - * must be paired with blkg_conf_finish(). + * result. @ctx->blkg points to the blkg to be updated and @ctx->body the + * part of @input following MAJ:MIN. This function returns with RCU read + * lock and queue lock held and must be paired with blkg_conf_finish(). */ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, - const char *input, struct blkg_conf_ctx *ctx) + char *input, struct blkg_conf_ctx *ctx) __acquires(rcu) __acquires(disk->queue->queue_lock) { struct gendisk *disk; struct blkcg_gq *blkg; unsigned int major, minor; - unsigned long long v; - int part, ret; + int key_len, part, ret; + char *body; - if (sscanf(input, "%u:%u %llu", &major, &minor, &v) != 3) + 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; @@ -826,7 +832,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, ctx->disk = disk; ctx->blkg = blkg; - ctx->v = v; + ctx->body = body; return 0; } EXPORT_SYMBOL_GPL(blkg_conf_prep); diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8b4f6b81bb72..0e17c8f92d25 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -1154,21 +1154,25 @@ static ssize_t tg_set_conf(struct kernfs_open_file *of, struct blkcg_gq *blkg; struct cgroup_subsys_state *pos_css; int ret; + u64 v; ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); if (ret) return ret; + ret = -EINVAL; + if (sscanf(ctx.body, "%llu", &v) != 1) + goto out_finish; + if (!v) + v = -1; + tg = blkg_to_tg(ctx.blkg); sq = &tg->service_queue; - if (!ctx.v) - ctx.v = -1; - if (is_u64) - *(u64 *)((void *)tg + of_cft(of)->private) = ctx.v; + *(u64 *)((void *)tg + of_cft(of)->private) = v; else - *(unsigned int *)((void *)tg + of_cft(of)->private) = ctx.v; + *(unsigned int *)((void *)tg + of_cft(of)->private) = v; throtl_log(&tg->service_queue, "limit change rbps=%llu wbps=%llu riops=%u wiops=%u", @@ -1201,8 +1205,10 @@ static ssize_t tg_set_conf(struct kernfs_open_file *of, throtl_schedule_next_dispatch(sq->parent_sq, true); } + ret = 0; +out_finish: blkg_conf_finish(&ctx); - return nbytes; + return ret ?: nbytes; } static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index baa8459f7064..ea88d8905bbd 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1747,26 +1747,31 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of, struct cfq_group *cfqg; struct cfq_group_data *cfqgd; int ret; + u64 v; ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx); if (ret) return ret; + ret = -EINVAL; + if (sscanf(ctx.body, "%llu", &v) != 1) + goto out_finish; + cfqg = blkg_to_cfqg(ctx.blkg); cfqgd = blkcg_to_cfqgd(blkcg); ret = -ERANGE; - if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) { + if (!v || (v >= CFQ_WEIGHT_MIN && v <= CFQ_WEIGHT_MAX)) { if (!is_leaf_weight) { - cfqg->dev_weight = ctx.v; - cfqg->new_weight = ctx.v ?: cfqgd->weight; + cfqg->dev_weight = v; + cfqg->new_weight = v ?: cfqgd->weight; } else { - cfqg->dev_leaf_weight = ctx.v; - cfqg->new_leaf_weight = ctx.v ?: cfqgd->leaf_weight; + cfqg->dev_leaf_weight = v; + cfqg->new_leaf_weight = v ?: cfqgd->leaf_weight; } ret = 0; } - +out_finish: blkg_conf_finish(&ctx); return ret ?: nbytes; } diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 6e016e6fee87..85a4d989ae43 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -206,11 +206,11 @@ struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkg_conf_ctx { struct gendisk *disk; struct blkcg_gq *blkg; - u64 v; + char *body; }; int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, - const char *input, struct blkg_conf_ctx *ctx); + char *input, struct blkg_conf_ctx *ctx); void blkg_conf_finish(struct blkg_conf_ctx *ctx);