Commit d03f6cdc authored by Jan Kara's avatar Jan Kara Committed by Jens Axboe
Browse files

block: Dynamically allocate and refcount backing_dev_info 



Instead of storing backing_dev_info inside struct request_queue,
allocate it dynamically, reference count it, and free it when the last
reference is dropped. Currently only request_queue holds the reference
but in the following patch we add other users referencing
backing_dev_info.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent dc3b17cc

block/blk-core.c

+5 −7
Original line number Diff line number Diff line
@@ -713,7 +713,6 @@ static void blk_rq_timed_out_timer(unsigned long data) 
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)

{

	struct request_queue *q;

	int err;



	q = kmem_cache_alloc_node(blk_requestq_cachep,

				gfp_mask | __GFP_ZERO, node_id);
@@ -728,17 +727,16 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) 
	if (!q->bio_split)

		goto fail_id;



	q->backing_dev_info = &q->_backing_dev_info;

	q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id);

	if (!q->backing_dev_info)

		goto fail_split;



	q->backing_dev_info->ra_pages =

			(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;

	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;

	q->backing_dev_info->name = "block";

	q->node = node_id;



	err = bdi_init(q->backing_dev_info);

	if (err)

		goto fail_split;



	setup_timer(&q->backing_dev_info->laptop_mode_wb_timer,

		    laptop_mode_timer_fn, (unsigned long) q);

	setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
@@ -789,7 +787,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) 
fail_ref:

	percpu_ref_exit(&q->q_usage_counter);

fail_bdi:

	bdi_destroy(q->backing_dev_info);

	bdi_put(q->backing_dev_info);

fail_split:

	bioset_free(q->bio_split);

fail_id:

block/blk-sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -799,7 +799,7 @@ static void blk_release_queue(struct kobject *kobj) 
		container_of(kobj, struct request_queue, kobj);



	wbt_exit(q);

	bdi_exit(q->backing_dev_info);

	bdi_put(q->backing_dev_info);

	blkcg_exit_queue(q);



	if (q->elevator) {

include/linux/backing-dev-defs.h

+2 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/flex_proportions.h>

#include <linux/timer.h>

#include <linux/workqueue.h>

#include <linux/kref.h>



struct page;

struct device;
@@ -144,6 +145,7 @@ struct backing_dev_info { 


	char *name;



	struct kref refcnt;	/* Reference counter for the structure */

	unsigned int capabilities; /* Device capabilities */

	unsigned int min_ratio;

	unsigned int max_ratio, max_prop_frac;

include/linux/backing-dev.h

+9 −1
Original line number Diff line number Diff line
@@ -18,7 +18,14 @@ 
#include <linux/slab.h>



int __must_check bdi_init(struct backing_dev_info *bdi);

void bdi_exit(struct backing_dev_info *bdi);



static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)

{

	kref_get(&bdi->refcnt);

	return bdi;

}



void bdi_put(struct backing_dev_info *bdi);



__printf(3, 4)

int bdi_register(struct backing_dev_info *bdi, struct device *parent,
@@ -29,6 +36,7 @@ void bdi_unregister(struct backing_dev_info *bdi); 


int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);

void bdi_destroy(struct backing_dev_info *bdi);

struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);



void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,

			bool range_cyclic, enum wb_reason reason);

include/linux/blkdev.h

+0 −1
Original line number Diff line number Diff line
@@ -433,7 +433,6 @@ struct request_queue { 
	struct delayed_work	delay_work;



	struct backing_dev_info	*backing_dev_info;

	struct backing_dev_info	_backing_dev_info;



	/*

	 * The queue owner gets to use this for whatever they like.

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