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@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 429726b..8ee1ca4 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 @@
* @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 @@
ctx->disk = disk;
ctx->blkg = blkg;
- ctx->v = v;
+ ctx->body = body;
return 0;
}
EXPORT_SYMBOL_GPL(blkg_conf_prep);