block: RCU free request_queue
RCU free request_queue so that blkcg_gq->q can be dereferenced under
RCU lock. This will be used to implement hierarchical stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 7881477..6206a93 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -497,6 +497,13 @@
return res;
}
+static void blk_free_queue_rcu(struct rcu_head *rcu_head)
+{
+ struct request_queue *q = container_of(rcu_head, struct request_queue,
+ rcu_head);
+ kmem_cache_free(blk_requestq_cachep, q);
+}
+
/**
* blk_release_queue: - release a &struct request_queue when it is no longer needed
* @kobj: the kobj belonging to the request queue to be released
@@ -538,7 +545,7 @@
bdi_destroy(&q->backing_dev_info);
ida_simple_remove(&blk_queue_ida, q->id);
- kmem_cache_free(blk_requestq_cachep, q);
+ call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
static const struct sysfs_ops queue_sysfs_ops = {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f94bc83..406343c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -19,6 +19,7 @@
#include <linux/gfp.h>
#include <linux/bsg.h>
#include <linux/smp.h>
+#include <linux/rcupdate.h>
#include <asm/scatterlist.h>
@@ -437,6 +438,7 @@
/* Throttle data */
struct throtl_data *td;
#endif
+ struct rcu_head rcu_head;
};
#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */