blkcg: make CONFIG_BLK_CGROUP bool
Block cgroup core can be built as module; however, it isn't too useful
as blk-throttle can only be built-in and cfq-iosched is usually the
default built-in scheduler. Scheduled blkcg cleanup requires calling
into blkcg from block core. To simplify that, disallow building blkcg
as module by making CONFIG_BLK_CGROUP bool.
If building blkcg core as module really matters, which I doubt, we can
revisit it after blkcg API cleanup.
-v2: Vivek pointed out that IOSCHED_CFQ was incorrectly updated to
depend on BLK_CGROUP. Fixed.
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/block/Kconfig.iosched b/block/Kconfig.iosched
index 3199b76..421bef9 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -23,8 +23,6 @@
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
- # If BLK_CGROUP is a module, CFQ has to be built as module.
- depends on (BLK_CGROUP=m && m) || !BLK_CGROUP || BLK_CGROUP=y
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
@@ -34,8 +32,6 @@
This is the default I/O scheduler.
- Note: If BLK_CGROUP=m, then CFQ can be built only as module.
-
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 75642a3..970a717 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -50,10 +50,7 @@
.attach = blkiocg_attach,
.destroy = blkiocg_destroy,
.populate = blkiocg_populate,
-#ifdef CONFIG_BLK_CGROUP
- /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
.subsys_id = blkio_subsys_id,
-#endif
.use_id = 1,
.module = THIS_MODULE,
};
@@ -1679,17 +1676,3 @@
spin_unlock(&blkio_list_lock);
}
EXPORT_SYMBOL_GPL(blkio_policy_unregister);
-
-static int __init init_cgroup_blkio(void)
-{
- return cgroup_load_subsys(&blkio_subsys);
-}
-
-static void __exit exit_cgroup_blkio(void)
-{
- cgroup_unload_subsys(&blkio_subsys);
-}
-
-module_init(init_cgroup_blkio);
-module_exit(exit_cgroup_blkio);
-MODULE_LICENSE("GPL");
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 6f3ace7..3551687 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -24,13 +24,7 @@
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX UINT_MAX
-#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
-
-#ifndef CONFIG_BLK_CGROUP
-/* When blk-cgroup is a module, its subsys_id isn't a compile-time constant */
-extern struct cgroup_subsys blkio_subsys;
-#define blkio_subsys_id blkio_subsys.subsys_id
-#endif
+#ifdef CONFIG_BLK_CGROUP
enum stat_type {
/* Total time spent (in ns) between request dispatch to the driver and
@@ -303,7 +297,7 @@
static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
#endif
-#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
+#ifdef CONFIG_BLK_CGROUP
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk);
diff --git a/init/Kconfig b/init/Kconfig
index 3f42cd6..da9222d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -766,7 +766,7 @@
endif #CGROUP_SCHED
config BLK_CGROUP
- tristate "Block IO controller"
+ bool "Block IO controller"
depends on BLOCK
default n
---help---