block: Use pointer to backing_dev_info from request_queue

We will want to have struct backing_dev_info allocated separately from
struct request_queue. As the first step add pointer to backing_dev_info
to request_queue and convert all users touching it. No functional
changes in this patch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Change-Id: I77fbb181de7e39c83fbfba8cfb128d6ace161f31
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
Git-commit: 97419acd22a0bacc52dbc34d5bbc96d315e48acb
[riteshh@codeaurora.org: resolved merge conflicts]
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>

block/blk-cgroup.c

@@ -184,7 +184,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 		goto err_free_blkg;
 	}
 
-	wb_congested = wb_congested_get_create(&q->backing_dev_info,
+	wb_congested = wb_congested_get_create(q->backing_dev_info,
 					       blkcg->css.id, GFP_NOWAIT);
 	if (!wb_congested) {
 		ret = -ENOMEM;
@@ -468,8 +468,8 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css,
 const char *blkg_dev_name(struct blkcg_gq *blkg)
 {
 	/* some drivers (floppy) instantiate a queue w/o disk registered */
-	if (blkg->q->backing_dev_info.dev)
-		return dev_name(blkg->q->backing_dev_info.dev);
+	if (blkg->q->backing_dev_info->dev)
+		return dev_name(blkg->q->backing_dev_info->dev);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(blkg_dev_name);

block/blk-core.c

@@ -87,7 +87,7 @@ static void blk_clear_congested(struct request_list *rl, int sync)
 	 * flip its congestion state for events on other blkcgs.
 	 */
 	if (rl == &rl->q->root_rl)
-		clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+		clear_wb_congested(rl->q->backing_dev_info->wb.congested, sync);
 #endif
 }
 
@@ -98,7 +98,7 @@ static void blk_set_congested(struct request_list *rl, int sync)
 #else
 	/* see blk_clear_congested() */
 	if (rl == &rl->q->root_rl)
-		set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+		set_wb_congested(rl->q->backing_dev_info->wb.congested, sync);
 #endif
 }
 
@@ -129,7 +129,7 @@ struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
 {
 	struct request_queue *q = bdev_get_queue(bdev);
 
-	return &q->backing_dev_info;
+	return q->backing_dev_info;
 }
 EXPORT_SYMBOL(blk_get_backing_dev_info);
 
@@ -597,7 +597,7 @@ void blk_cleanup_queue(struct request_queue *q)
 	blk_flush_integrity();
 
 	/* @q won't process any more request, flush async actions */
-	del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
+	del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer);
 	blk_sync_queue(q);
 
 	if (q->mq_ops)
@@ -712,17 +712,18 @@ 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.ra_pages =
+	q->backing_dev_info = &q->_backing_dev_info;
+	q->backing_dev_info->ra_pages =
 			(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
-	q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
-	q->backing_dev_info.name = "block";
+	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);
+	err = bdi_init(q->backing_dev_info);
 	if (err)
 		goto fail_split;
 
-	setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
+	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);
 	INIT_LIST_HEAD(&q->queue_head);
@@ -772,7 +773,7 @@ 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_destroy(q->backing_dev_info);
 fail_split:
 	bioset_free(q->bio_split);
 fail_id:
@@ -1195,7 +1196,7 @@ fail_elvpriv:
 	 * disturb iosched and blkcg but weird is bettern than dead.
 	 */
 	printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n",
-			   __func__, dev_name(q->backing_dev_info.dev));
+			   __func__, dev_name(q->backing_dev_info->dev));
 
 	rq->cmd_flags &= ~REQ_ELVPRIV;
 	rq->elv.icq = NULL;
@@ -3251,7 +3252,7 @@ void blk_finish_request(struct request *req, int error)
 	BUG_ON(blk_queued_rq(req));
 
 	if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS)
-		laptop_io_completion(&req->q->backing_dev_info);
+		laptop_io_completion(req->q->backing_dev_info);
 
 	blk_delete_timer(req);
 

block/blk-integrity.c

@@ -418,7 +418,7 @@ void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template
 	bi->tuple_size = template->tuple_size;
 	bi->tag_size = template->tag_size;
 
-	disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES;
+	disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
 }
 EXPORT_SYMBOL(blk_integrity_register);
 
@@ -431,7 +431,7 @@ EXPORT_SYMBOL(blk_integrity_register);
  */
 void blk_integrity_unregister(struct gendisk *disk)
 {
-	disk->queue->backing_dev_info.capabilities &= ~BDI_CAP_STABLE_WRITES;
+	disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
 	memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
 }
 EXPORT_SYMBOL(blk_integrity_unregister);

block/blk-sysfs.c

@@ -75,7 +75,7 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count)
 
 static ssize_t queue_ra_show(struct request_queue *q, char *page)
 {
-	unsigned long ra_kb = q->backing_dev_info.ra_pages <<
+	unsigned long ra_kb = q->backing_dev_info->ra_pages <<
 					(PAGE_CACHE_SHIFT - 10);
 
 	return queue_var_show(ra_kb, (page));
@@ -90,7 +90,7 @@ queue_ra_store(struct request_queue *q, const char *page, size_t count)
 	if (ret < 0)
 		return ret;
 
-	q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
+	q->backing_dev_info->ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
 
 	return ret;
 }
@@ -578,7 +578,7 @@ static void blk_release_queue(struct kobject *kobj)
 	struct request_queue *q =
 		container_of(kobj, struct request_queue, kobj);
 
-	bdi_exit(&q->backing_dev_info);
+	bdi_exit(q->backing_dev_info);
 	blkcg_exit_queue(q);
 
 	if (q->elevator) {

block/genhd.c

@@ -611,7 +611,7 @@ void add_disk(struct gendisk *disk)
 	disk_alloc_events(disk);
 
 	/* Register BDI before referencing it from bdev */
-	bdi = &disk->queue->backing_dev_info;
+	bdi = disk->queue->backing_dev_info;
 	bdi_register_owner(bdi, disk_to_dev(disk));
 
 	blk_register_region(disk_devt(disk), disk->minors, NULL,
@@ -663,7 +663,7 @@ void del_gendisk(struct gendisk *disk)
 		 * Unregister bdi before releasing device numbers (as they can
 		 * get reused and we'd get clashes in sysfs).
 		 */
-		bdi_unregister(&disk->queue->backing_dev_info);
+		bdi_unregister(disk->queue->backing_dev_info);
 		blk_unregister_queue(disk);
 	} else {
 		WARN_ON(1);

drivers/block/aoe/aoeblk.c

@@ -396,8 +396,8 @@ aoeblk_gdalloc(void *vp)
 	WARN_ON(d->gd);
 	WARN_ON(d->flags & DEVFL_UP);
 	blk_queue_max_hw_sectors(q, BLK_DEF_MAX_SECTORS);
-	q->backing_dev_info.name = "aoe";
-	q->backing_dev_info.ra_pages = READ_AHEAD / PAGE_CACHE_SIZE;
+	q->backing_dev_info->name = "aoe";
+	q->backing_dev_info->ra_pages = READ_AHEAD / PAGE_CACHE_SIZE;
 	d->bufpool = mp;
 	d->blkq = gd->queue = q;
 	q->queuedata = d;

drivers/block/drbd/drbd_main.c

@@ -2393,7 +2393,7 @@ static int drbd_congested(void *congested_data, int bdi_bits)
 
 	if (get_ldev(device)) {
 		q = bdev_get_queue(device->ldev->backing_bdev);
-		r = bdi_congested(&q->backing_dev_info, bdi_bits);
+		r = bdi_congested(q->backing_dev_info, bdi_bits);
 		put_ldev(device);
 		if (r)
 			reason = 'b';
@@ -2765,8 +2765,8 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 	/* we have no partitions. we contain only ourselves. */
 	device->this_bdev->bd_contains = device->this_bdev;
 
-	q->backing_dev_info.congested_fn = drbd_congested;
-	q->backing_dev_info.congested_data = device;
+	q->backing_dev_info->congested_fn = drbd_congested;
+	q->backing_dev_info->congested_data = device;
 
 	blk_queue_make_request(q, drbd_make_request);
 	blk_queue_flush(q, REQ_FLUSH | REQ_FUA);

drivers/block/drbd/drbd_nl.c

@@ -1170,11 +1170,11 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
 
 		blk_queue_stack_limits(q, b);
 
-		if (q->backing_dev_info.ra_pages != b->backing_dev_info.ra_pages) {
+		if (q->backing_dev_info->ra_pages != b->backing_dev_info->ra_pages) {
 			drbd_info(device, "Adjusting my ra_pages to backing device's (%lu -> %lu)\n",
-				 q->backing_dev_info.ra_pages,
-				 b->backing_dev_info.ra_pages);
-			q->backing_dev_info.ra_pages = b->backing_dev_info.ra_pages;
+				 q->backing_dev_info->ra_pages,
+				 b->backing_dev_info->ra_pages);
+			q->backing_dev_info->ra_pages = b->backing_dev_info->ra_pages;
 		}
 	}
 }

drivers/block/drbd/drbd_proc.c

@@ -288,7 +288,7 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
 			seq_printf(seq, "%2d: cs:Unconfigured\n", i);
 		} else {
 			/* reset device->congestion_reason */
-			bdi_rw_congested(&device->rq_queue->backing_dev_info);
+			bdi_rw_congested(device->rq_queue->backing_dev_info);
 
 			nc = rcu_dereference(first_peer_device(device)->connection->net_conf);
 			wp = nc ? nc->wire_protocol - DRBD_PROT_A + 'A' : ' ';

drivers/block/drbd/drbd_req.c

@@ -937,7 +937,7 @@ static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t se
 
 	switch (rbm) {
 	case RB_CONGESTED_REMOTE:
-		bdi = &device->ldev->backing_bdev->bd_disk->queue->backing_dev_info;
+		bdi = device->ldev->backing_bdev->bd_disk->queue->backing_dev_info;
 		return bdi_read_congested(bdi);
 	case RB_LEAST_PENDING:
 		return atomic_read(&device->local_cnt) >

drivers/block/pktcdvd.c

@@ -1276,7 +1276,7 @@ try_next_bio:
 	 		&& pd->bio_queue_size <= pd->write_congestion_off);
 	spin_unlock(&pd->lock);
 	if (wakeup) {
-		clear_bdi_congested(&pd->disk->queue->backing_dev_info,
+		clear_bdi_congested(pd->disk->queue->backing_dev_info,
 					BLK_RW_ASYNC);
 	}
 
@@ -2405,7 +2405,7 @@ static void pkt_make_request_write(struct request_queue *q, struct bio *bio)
 	spin_lock(&pd->lock);
 	if (pd->write_congestion_on > 0
 	    && pd->bio_queue_size >= pd->write_congestion_on) {
-		set_bdi_congested(&q->backing_dev_info, BLK_RW_ASYNC);
+		set_bdi_congested(q->backing_dev_info, BLK_RW_ASYNC);
 		do {
 			spin_unlock(&pd->lock);
 			congestion_wait(BLK_RW_ASYNC, HZ);

drivers/block/rbd.c

@@ -3780,7 +3780,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	q->limits.discard_zeroes_data = 1;
 
 	if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
-		q->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES;
+		q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
 
 	disk->queue = q;
 

drivers/md/bcache/request.c

@@ -1014,7 +1014,7 @@ static int cached_dev_congested(void *data, int bits)
 	struct request_queue *q = bdev_get_queue(dc->bdev);
 	int ret = 0;
 
-	if (bdi_congested(&q->backing_dev_info, bits))
+	if (bdi_congested(q->backing_dev_info, bits))
 		return 1;
 
 	if (cached_dev_get(dc)) {
@@ -1023,7 +1023,7 @@ static int cached_dev_congested(void *data, int bits)
 
 		for_each_cache(ca, d->c, i) {
 			q = bdev_get_queue(ca->bdev);
-			ret |= bdi_congested(&q->backing_dev_info, bits);
+			ret |= bdi_congested(q->backing_dev_info, bits);
 		}
 
 		cached_dev_put(dc);
@@ -1037,7 +1037,7 @@ void bch_cached_dev_request_init(struct cached_dev *dc)
 	struct gendisk *g = dc->disk.disk;
 
 	g->queue->make_request_fn		= cached_dev_make_request;
-	g->queue->backing_dev_info.congested_fn = cached_dev_congested;
+	g->queue->backing_dev_info->congested_fn = cached_dev_congested;
 	dc->disk.cache_miss			= cached_dev_cache_miss;
 	dc->disk.ioctl				= cached_dev_ioctl;
 }
@@ -1130,7 +1130,7 @@ static int flash_dev_congested(void *data, int bits)
 
 	for_each_cache(ca, d->c, i) {
 		q = bdev_get_queue(ca->bdev);
-		ret |= bdi_congested(&q->backing_dev_info, bits);
+		ret |= bdi_congested(q->backing_dev_info, bits);
 	}
 
 	return ret;
@@ -1141,7 +1141,7 @@ void bch_flash_dev_request_init(struct bcache_device *d)
 	struct gendisk *g = d->disk;
 
 	g->queue->make_request_fn		= flash_dev_make_request;
-	g->queue->backing_dev_info.congested_fn = flash_dev_congested;
+	g->queue->backing_dev_info->congested_fn = flash_dev_congested;
 	d->cache_miss				= flash_dev_cache_miss;
 	d->ioctl				= flash_dev_ioctl;
 }

drivers/md/bcache/super.c

@@ -802,7 +802,7 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 	blk_queue_make_request(q, NULL);
 	d->disk->queue			= q;
 	q->queuedata			= d;
-	q->backing_dev_info.congested_data = d;
+	q->backing_dev_info->congested_data = d;
 	q->limits.max_hw_sectors	= UINT_MAX;
 	q->limits.max_sectors		= UINT_MAX;
 	q->limits.max_segment_size	= UINT_MAX;
@@ -1129,9 +1129,9 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
 	set_capacity(dc->disk.disk,
 		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
 
-	dc->disk.disk->queue->backing_dev_info.ra_pages =
-		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
-		    q->backing_dev_info.ra_pages);
+	dc->disk.disk->queue->backing_dev_info->ra_pages =
+		max(dc->disk.disk->queue->backing_dev_info->ra_pages,
+		    q->backing_dev_info->ra_pages);
 
 	bch_cached_dev_request_init(dc);
 	bch_cached_dev_writeback_init(dc);

drivers/md/dm-cache-target.c

@@ -2288,7 +2288,7 @@ static void do_waker(struct work_struct *ws)
 static int is_congested(struct dm_dev *dev, int bdi_bits)
 {
 	struct request_queue *q = bdev_get_queue(dev->bdev);
-	return bdi_congested(&q->backing_dev_info, bdi_bits);
+	return bdi_congested(q->backing_dev_info, bdi_bits);
 }
 
 static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)

drivers/md/dm-era-target.c

@@ -1379,7 +1379,7 @@ static void stop_worker(struct era *era)
 static int dev_is_congested(struct dm_dev *dev, int bdi_bits)
 {
 	struct request_queue *q = bdev_get_queue(dev->bdev);
-	return bdi_congested(&q->backing_dev_info, bdi_bits);
+	return bdi_congested(q->backing_dev_info, bdi_bits);
 }
 
 static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits)

drivers/md/dm-table.c

@@ -1660,7 +1660,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
 		char b[BDEVNAME_SIZE];
 
 		if (likely(q))
-			r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+			r |= bdi_congested(q->backing_dev_info, bdi_bits);
 		else
 			DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
 				     dm_device_name(t->md),

drivers/md/dm-thin.c

@@ -2634,7 +2634,7 @@ static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
 		return 1;
 
 	q = bdev_get_queue(pt->data_dev->bdev);
-	return bdi_congested(&q->backing_dev_info, bdi_bits);
+	return bdi_congested(q->backing_dev_info, bdi_bits);
 }
 
 static void requeue_bios(struct pool *pool)

drivers/md/dm.c

@@ -2220,7 +2220,7 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
 			 * the query about congestion status of request_queue
 			 */
 			if (dm_request_based(md))
-				r = md->queue->backing_dev_info.wb.state &
+				r = md->queue->backing_dev_info->wb.state &
 				    bdi_bits;
 			else
 				r = dm_table_any_congested(map, bdi_bits);
@@ -2302,7 +2302,7 @@ static void dm_init_md_queue(struct mapped_device *md)
 	 * - must do so here (in alloc_dev callchain) before queue is used
 	 */
 	md->queue->queuedata = md;
-	md->queue->backing_dev_info.congested_data = md;
+	md->queue->backing_dev_info->congested_data = md;
 }
 
 static void dm_init_old_md_queue(struct mapped_device *md)
@@ -2313,7 +2313,7 @@ static void dm_init_old_md_queue(struct mapped_device *md)
 	/*
 	 * Initialize aspects of queue that aren't relevant for blk-mq
 	 */
-	md->queue->backing_dev_info.congested_fn = dm_any_congested;
+	md->queue->backing_dev_info->congested_fn = dm_any_congested;
 	blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
 }
 

drivers/md/linear.c

@@ -68,7 +68,7 @@ static int linear_congested(struct mddev *mddev, int bits)
 
 	for (i = 0; i < conf->raid_disks && !ret ; i++) {
 		struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
-		ret |= bdi_congested(&q->backing_dev_info, bits);
+		ret |= bdi_congested(q->backing_dev_info, bits);
 	}
 
 	rcu_read_unlock();

drivers/md/md.c

@@ -5284,8 +5284,8 @@ int md_run(struct mddev *mddev)
 		return err;
 	}
 	if (mddev->queue) {
-		mddev->queue->backing_dev_info.congested_data = mddev;
-		mddev->queue->backing_dev_info.congested_fn = md_congested;
+		mddev->queue->backing_dev_info->congested_data = mddev;
+		mddev->queue->backing_dev_info->congested_fn = md_congested;
 	}
 	if (pers->sync_request) {
 		if (mddev->kobj.sd &&
@@ -5642,7 +5642,7 @@ static int do_md_stop(struct mddev *mddev, int mode,
 
 		__md_stop_writes(mddev);
 		__md_stop(mddev);
-		mddev->queue->backing_dev_info.congested_fn = NULL;
+		mddev->queue->backing_dev_info->congested_fn = NULL;
 
 		/* tell userspace to handle 'inactive' */
 		sysfs_notify_dirent_safe(mddev->sysfs_state);

drivers/md/multipath.c

@@ -166,7 +166,7 @@ static int multipath_congested(struct mddev *mddev, int bits)
 		if (rdev && !test_bit(Faulty, &rdev->flags)) {
 			struct request_queue *q = bdev_get_queue(rdev->bdev);
 
-			ret |= bdi_congested(&q->backing_dev_info, bits);
+			ret |= bdi_congested(q->backing_dev_info, bits);
 			/* Just like multipath_map, we just check the
 			 * first available device
 			 */

drivers/md/raid0.c

@@ -35,7 +35,7 @@ static int raid0_congested(struct mddev *mddev, int bits)
 	for (i = 0; i < raid_disks && !ret ; i++) {
 		struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
 
-		ret |= bdi_congested(&q->backing_dev_info, bits);
+		ret |= bdi_congested(q->backing_dev_info, bits);
 	}
 	return ret;
 }
@@ -415,8 +415,8 @@ static int raid0_run(struct mddev *mddev)
 		 */
 		int stripe = mddev->raid_disks *
 			(mddev->chunk_sectors << 9) / PAGE_SIZE;
-		if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
-			mddev->queue->backing_dev_info.ra_pages = 2* stripe;
+		if (mddev->queue->backing_dev_info->ra_pages < 2* stripe)
+			mddev->queue->backing_dev_info->ra_pages = 2* stripe;
 	}
 
 	dump_zones(mddev);

drivers/md/raid1.c

@@ -730,9 +730,9 @@ static int raid1_congested(struct mddev *mddev, int bits)
 			 * non-congested targets, it can be removed
 			 */
 			if ((bits & (1 << WB_async_congested)) || 1)
-				ret |= bdi_congested(&q->backing_dev_info, bits);
+				ret |= bdi_congested(q->backing_dev_info, bits);
 			else
-				ret &= bdi_congested(&q->backing_dev_info, bits);
+				ret &= bdi_congested(q->backing_dev_info, bits);
 		}
 	}
 	rcu_read_unlock();

drivers/md/raid10.c

@@ -838,7 +838,7 @@ static int raid10_congested(struct mddev *mddev, int bits)
 		if (rdev && !test_bit(Faulty, &rdev->flags)) {
 			struct request_queue *q = bdev_get_queue(rdev->bdev);
 
-			ret |= bdi_congested(&q->backing_dev_info, bits);
+			ret |= bdi_congested(q->backing_dev_info, bits);
 		}
 	}
 	rcu_read_unlock();
@@ -3698,8 +3698,8 @@ static int run(struct mddev *mddev)
 		 * maybe...
 		 */
 		stripe /= conf->geo.near_copies;
-		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
-			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+		if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
+			mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
 	}
 
 	if (md_integrity_register(mddev))
@@ -4493,8 +4493,8 @@ static void end_reshape(struct r10conf *conf)
 		int stripe = conf->geo.raid_disks *
 			((conf->mddev->chunk_sectors << 9) / PAGE_SIZE);
 		stripe /= conf->geo.near_copies;
-		if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
-			conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+		if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
+			conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
 	}
 	conf->fullsync = 0;
 }

drivers/md/raid5.c

@@ -6123,10 +6123,10 @@ raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
 		mddev_suspend(mddev);
 		conf->skip_copy = new;
 		if (new)
-			mddev->queue->backing_dev_info.capabilities |=
+			mddev->queue->backing_dev_info->capabilities |=
 				BDI_CAP_STABLE_WRITES;
 		else
-			mddev->queue->backing_dev_info.capabilities &=
+			mddev->queue->backing_dev_info->capabilities &=
 				~BDI_CAP_STABLE_WRITES;
 		mddev_resume(mddev);
 	}
@@ -6970,8 +6970,8 @@ static int run(struct mddev *mddev)
 		int data_disks = conf->previous_raid_disks - conf->max_degraded;
 		int stripe = data_disks *
 			((mddev->chunk_sectors << 9) / PAGE_SIZE);
-		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
-			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+		if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
+			mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
 
 		chunk_size = mddev->chunk_sectors << 9;
 		blk_queue_io_min(mddev->queue, chunk_size);
@@ -7552,8 +7552,8 @@ static void end_reshape(struct r5conf *conf)
 			int data_disks = conf->raid_disks - conf->max_degraded;
 			int stripe = data_disks * ((conf->chunk_sectors << 9)
 						   / PAGE_SIZE);
-			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
-				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+			if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
+				conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
 		}
 	}
 }

fs/gfs2/ops_fstype.c

@@ -1222,7 +1222,7 @@ static int set_gfs2_super(struct super_block *s, void *data)
 	 * We set the bdi here to the queue backing, file systems can
 	 * overwrite this in ->fill_super()
 	 */
-	s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
+	s->s_bdi = bdev_get_queue(s->s_bdev)->backing_dev_info;
 	return 0;
 }
 

fs/nilfs2/super.c

@@ -1079,7 +1079,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_time_gran = 1;
 	sb->s_max_links = NILFS_LINK_MAX;
 
-	sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
+	sb->s_bdi = bdev_get_queue(sb->s_bdev)->backing_dev_info;
 
 	err = load_nilfs(nilfs, sb);
 	if (err)

fs/super.c

@@ -968,7 +968,7 @@ static int set_bdev_super(struct super_block *s, void *data)
 	 * We set the bdi here to the queue backing, file systems can
 	 * overwrite this in ->fill_super()
 	 */
-	s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
+	s->s_bdi = bdev_get_queue(s->s_bdev)->backing_dev_info;
 	return 0;
 }
 

include/linux/blkdev.h

@@ -332,7 +332,8 @@ struct request_queue {
 	 */
 	struct delayed_work	delay_work;
 
-	struct backing_dev_info	backing_dev_info;
+	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.

mm/page-writeback.c

@@ -1993,11 +1993,11 @@ void laptop_mode_timer_fn(unsigned long data)
 	 * We want to write everything out, not just down to the dirty
 	 * threshold
 	 */
-	if (!bdi_has_dirty_io(&q->backing_dev_info))
+	if (!bdi_has_dirty_io(q->backing_dev_info))
 		return;
 
 	rcu_read_lock();
-	list_for_each_entry_rcu(wb, &q->backing_dev_info.wb_list, bdi_node)
+	list_for_each_entry_rcu(wb, &q->backing_dev_info->wb_list, bdi_node)
 		if (wb_has_dirty_io(wb))
 			wb_start_writeback(wb, nr_pages, true,
 					   WB_REASON_LAPTOP_TIMER);