Commit 548bc8e1 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
parent 16b3de66

block/blk-sysfs.c

+8 −1
Original line number Diff line number Diff line
@@ -497,6 +497,13 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr, 
	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 @@ static void blk_release_queue(struct kobject *kobj) 
	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 = {

include/linux/blkdev.h

+2 −0
Original line number Diff line number Diff line
@@ -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 @@ struct request_queue { 
	/* Throttle data */

	struct throtl_data *td;

#endif

	struct rcu_head		rcu_head;

};



#define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */