blkcg: remove static policy ID enums
Remove BLKIO_POLICY_* enums and let blkio_policy_register() allocate
@pol->plid dynamically on registration. The maximum number of blkcg
policies which can be registered at the same time is defined by
BLKCG_MAX_POLS constant added to include/linux/blkdev.h.
Note that blkio_policy_register() now may fail. Policy init functions
updated accordingly and unnecessary ifdefs removed from cfq_init().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 33f1b29..d2c69f8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -35,6 +35,12 @@
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
+/*
+ * Maximum number of blkcg policies allowed to be registered concurrently.
+ * Defined here to simplify include dependency.
+ */
+#define BLKCG_MAX_POLS 2
+
struct request;
typedef void (rq_end_io_fn)(struct request *, int);
@@ -363,7 +369,6 @@
struct list_head icq_list;
#ifdef CONFIG_BLK_CGROUP
- /* XXX: array size hardcoded to avoid include dependency (temporary) */
struct list_head blkg_list;
#endif