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Date: Fri, 24 Jul 2015 14:43:51 -0400
From: Tejun Heo <tj@...nel.org>
To: axboe@...nel.dk
Cc: vgoyal@...hat.com, linux-kernel@...r.kernel.org,
avanzini.arianna@...il.com, kernel-team@...com, hannes@...xchg.org,
lizefan@...wei.com, cgroups@...r.kernel.org,
Tejun Heo <tj@...nel.org>
Subject: [PATCH 07/10] 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 <tj@...nel.org>
---
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 db7b3cc..2ea3a2a 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -24,6 +24,7 @@
#include <linux/genhd.h>
#include <linux/delay.h>
#include <linux/atomic.h>
+#include <linux/ctype.h>
#include <linux/blk-cgroup.h>
#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 8b4f6b8..0e17c8f 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 baa8459..ea88d89 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 6e016e6..85a4d98 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);
--
2.4.3
--
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