Re: [PATCH 15/15] blk-cgroup: move the cgroup information to struct gendisk

[Andreas Herrmann <aherrmann-l3A5Bk7waGM@public.gmane.org>]

On Tue, Jan 17, 2023 at 09:12:57AM +0100, Christoph Hellwig wrote:
> cgroup information only makes sense on a live gendisk that allows
> file system I/O (which includes the raw block device).  So move over
> the cgroup related members.
> 
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> ---
>  block/bfq-cgroup.c     |  4 ++--
>  block/blk-cgroup.c     | 48 +++++++++++++++++++++---------------------
>  block/blk-cgroup.h     |  2 +-
>  block/blk-iolatency.c  |  2 +-
>  block/blk-throttle.c   | 16 ++++++++------
>  include/linux/blkdev.h | 10 ++++-----
>  6 files changed, 43 insertions(+), 39 deletions(-)

Looks good to me. Feel free to add
Reviewed-by: Andreas Herrmann <aherrmann-l3A5Bk7waGM@public.gmane.org>

> diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
> index 055f9684c1c502..c13ba851c5221a 100644
> --- a/block/bfq-cgroup.c
> +++ b/block/bfq-cgroup.c
> @@ -1003,7 +1003,7 @@ void bfq_end_wr_async(struct bfq_data *bfqd)
>  {
>  	struct blkcg_gq *blkg;
>  
> -	list_for_each_entry(blkg, &bfqd->queue->blkg_list, q_node) {
> +	list_for_each_entry(blkg, &bfqd->queue->disk->blkg_list, q_node) {
>  		struct bfq_group *bfqg = blkg_to_bfqg(blkg);
>  
>  		bfq_end_wr_async_queues(bfqd, bfqg);
> @@ -1297,7 +1297,7 @@ struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
>  	if (ret)
>  		return NULL;
>  
> -	return blkg_to_bfqg(bfqd->queue->root_blkg);
> +	return blkg_to_bfqg(bfqd->queue->disk->root_blkg);
>  }
>  
>  struct blkcg_policy blkcg_policy_bfq = {
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index a041b3ddab6e33..0c813b50275cf1 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -108,10 +108,10 @@ static struct cgroup_subsys_state *blkcg_css(void)
>  	return task_css(current, io_cgrp_id);
>  }
>  
> -static bool blkcg_policy_enabled(struct request_queue *q,
> +static bool blkcg_policy_enabled(struct gendisk *disk,
>  				 const struct blkcg_policy *pol)
>  {
> -	return pol && test_bit(pol->plid, q->blkcg_pols);
> +	return pol && test_bit(pol->plid, disk->blkcg_pols);
>  }
>  
>  /**
> @@ -264,7 +264,7 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk,
>  		struct blkcg_policy *pol = blkcg_policy[i];
>  		struct blkg_policy_data *pd;
>  
> -		if (!blkcg_policy_enabled(disk->queue, pol))
> +		if (!blkcg_policy_enabled(disk, pol))
>  			continue;
>  
>  		/* alloc per-policy data and attach it to blkg */
> @@ -341,7 +341,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, struct gendisk *disk,
>  	ret = radix_tree_insert(&blkcg->blkg_tree, disk->queue->id, blkg);
>  	if (likely(!ret)) {
>  		hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
> -		list_add(&blkg->q_node, &disk->queue->blkg_list);
> +		list_add(&blkg->q_node, &disk->blkg_list);
>  
>  		for (i = 0; i < BLKCG_MAX_POLS; i++) {
>  			struct blkcg_policy *pol = blkcg_policy[i];
> @@ -410,7 +410,7 @@ static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
>  	while (true) {
>  		struct blkcg *pos = blkcg;
>  		struct blkcg *parent = blkcg_parent(blkcg);
> -		struct blkcg_gq *ret_blkg = q->root_blkg;
> +		struct blkcg_gq *ret_blkg = disk->root_blkg;
>  
>  		while (parent) {
>  			blkg = blkg_lookup(parent, disk);
> @@ -485,7 +485,7 @@ static void blkg_destroy_all(struct gendisk *disk)
>  
>  restart:
>  	spin_lock_irq(&q->queue_lock);
> -	list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
> +	list_for_each_entry_safe(blkg, n, &disk->blkg_list, q_node) {
>  		struct blkcg *blkcg = blkg->blkcg;
>  
>  		spin_lock(&blkcg->lock);
> @@ -504,7 +504,7 @@ static void blkg_destroy_all(struct gendisk *disk)
>  		}
>  	}
>  
> -	q->root_blkg = NULL;
> +	disk->root_blkg = NULL;
>  	spin_unlock_irq(&q->queue_lock);
>  }
>  
> @@ -579,7 +579,7 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
>  	rcu_read_lock();
>  	hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
>  		spin_lock_irq(&blkg->disk->queue->queue_lock);
> -		if (blkcg_policy_enabled(blkg->disk->queue, pol))
> +		if (blkcg_policy_enabled(blkg->disk, pol))
>  			total += prfill(sf, blkg->pd[pol->plid], data);
>  		spin_unlock_irq(&blkg->disk->queue->queue_lock);
>  	}
> @@ -687,7 +687,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
>  	rcu_read_lock();
>  	spin_lock_irq(&q->queue_lock);
>  
> -	if (!blkcg_policy_enabled(q, pol)) {
> +	if (!blkcg_policy_enabled(disk, pol)) {
>  		ret = -EOPNOTSUPP;
>  		goto fail_unlock;
>  	}
> @@ -730,7 +730,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
>  		rcu_read_lock();
>  		spin_lock_irq(&q->queue_lock);
>  
> -		if (!blkcg_policy_enabled(q, pol)) {
> +		if (!blkcg_policy_enabled(disk, pol)) {
>  			blkg_free(new_blkg);
>  			ret = -EOPNOTSUPP;
>  			goto fail_preloaded;
> @@ -910,7 +910,7 @@ static void blkcg_fill_root_iostats(void)
>  	class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
>  	while ((dev = class_dev_iter_next(&iter))) {
>  		struct block_device *bdev = dev_to_bdev(dev);
> -		struct blkcg_gq *blkg = bdev->bd_disk->queue->root_blkg;
> +		struct blkcg_gq *blkg = bdev->bd_disk->root_blkg;
>  		struct blkg_iostat tmp;
>  		int cpu;
>  		unsigned long flags;
> @@ -1257,7 +1257,7 @@ int blkcg_init_disk(struct gendisk *disk)
>  	bool preloaded;
>  	int ret;
>  
> -	INIT_LIST_HEAD(&q->blkg_list);
> +	INIT_LIST_HEAD(&disk->blkg_list);
>  
>  	new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL);
>  	if (!new_blkg)
> @@ -1271,7 +1271,7 @@ int blkcg_init_disk(struct gendisk *disk)
>  	blkg = blkg_create(&blkcg_root, disk, new_blkg);
>  	if (IS_ERR(blkg))
>  		goto err_unlock;
> -	q->root_blkg = blkg;
> +	disk->root_blkg = blkg;
>  	spin_unlock_irq(&q->queue_lock);
>  
>  	if (preloaded)
> @@ -1384,7 +1384,7 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol)
>  	struct blkcg_gq *blkg, *pinned_blkg = NULL;
>  	int ret;
>  
> -	if (blkcg_policy_enabled(q, pol))
> +	if (blkcg_policy_enabled(disk, pol))
>  		return 0;
>  
>  	if (queue_is_mq(q))
> @@ -1393,7 +1393,7 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol)
>  	spin_lock_irq(&q->queue_lock);
>  
>  	/* blkg_list is pushed at the head, reverse walk to allocate parents first */
> -	list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) {
> +	list_for_each_entry_reverse(blkg, &disk->blkg_list, q_node) {
>  		struct blkg_policy_data *pd;
>  
>  		if (blkg->pd[pol->plid])
> @@ -1437,10 +1437,10 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol)
>  
>  	/* all allocated, init in the same order */
>  	if (pol->pd_init_fn)
> -		list_for_each_entry_reverse(blkg, &q->blkg_list, q_node)
> +		list_for_each_entry_reverse(blkg, &disk->blkg_list, q_node)
>  			pol->pd_init_fn(blkg->pd[pol->plid]);
>  
> -	__set_bit(pol->plid, q->blkcg_pols);
> +	__set_bit(pol->plid, disk->blkcg_pols);
>  	ret = 0;
>  
>  	spin_unlock_irq(&q->queue_lock);
> @@ -1456,7 +1456,7 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol)
>  enomem:
>  	/* alloc failed, nothing's initialized yet, free everything */
>  	spin_lock_irq(&q->queue_lock);
> -	list_for_each_entry(blkg, &q->blkg_list, q_node) {
> +	list_for_each_entry(blkg, &disk->blkg_list, q_node) {
>  		struct blkcg *blkcg = blkg->blkcg;
>  
>  		spin_lock(&blkcg->lock);
> @@ -1486,7 +1486,7 @@ void blkcg_deactivate_policy(struct gendisk *disk,
>  	struct request_queue *q = disk->queue;
>  	struct blkcg_gq *blkg;
>  
> -	if (!blkcg_policy_enabled(q, pol))
> +	if (!blkcg_policy_enabled(disk, pol))
>  		return;
>  
>  	if (queue_is_mq(q))
> @@ -1494,9 +1494,9 @@ void blkcg_deactivate_policy(struct gendisk *disk,
>  
>  	spin_lock_irq(&q->queue_lock);
>  
> -	__clear_bit(pol->plid, q->blkcg_pols);
> +	__clear_bit(pol->plid, disk->blkcg_pols);
>  
> -	list_for_each_entry(blkg, &q->blkg_list, q_node) {
> +	list_for_each_entry(blkg, &disk->blkg_list, q_node) {
>  		struct blkcg *blkcg = blkg->blkcg;
>  
>  		spin_lock(&blkcg->lock);
> @@ -1909,7 +1909,7 @@ static inline struct blkcg_gq *blkg_tryget_closest(struct bio *bio,
>   * Associate @bio with the blkg found by combining the css's blkg and the
>   * request_queue of the @bio.  An association failure is handled by walking up
>   * the blkg tree.  Therefore, the blkg associated can be anything between @blkg
> - * and q->root_blkg.  This situation only happens when a cgroup is dying and
> + * and disk->root_blkg.  This situation only happens when a cgroup is dying and
>   * then the remaining bios will spill to the closest alive blkg.
>   *
>   * A reference will be taken on the blkg and will be released when @bio is
> @@ -1924,8 +1924,8 @@ void bio_associate_blkg_from_css(struct bio *bio,
>  	if (css && css->parent) {
>  		bio->bi_blkg = blkg_tryget_closest(bio, css);
>  	} else {
> -		blkg_get(bdev_get_queue(bio->bi_bdev)->root_blkg);
> -		bio->bi_blkg = bdev_get_queue(bio->bi_bdev)->root_blkg;
> +		blkg_get(bio->bi_bdev->bd_disk->root_blkg);
> +		bio->bi_blkg = bio->bi_bdev->bd_disk->root_blkg;
>  	}
>  }
>  EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
> diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
> index 3e7508907f33d8..81eca9be7f9105 100644
> --- a/block/blk-cgroup.h
> +++ b/block/blk-cgroup.h
> @@ -246,7 +246,7 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
>  	WARN_ON_ONCE(!rcu_read_lock_held());
>  
>  	if (blkcg == &blkcg_root)
> -		return disk->queue->root_blkg;
> +		return disk->root_blkg;
>  
>  	blkg = rcu_dereference(blkcg->blkg_hint);
>  	if (blkg && blkg->disk == disk)
> diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
> index bc0d217f5c1723..5d5aa1e526b742 100644
> --- a/block/blk-iolatency.c
> +++ b/block/blk-iolatency.c
> @@ -665,7 +665,7 @@ static void blkiolatency_timer_fn(struct timer_list *t)
>  
>  	rcu_read_lock();
>  	blkg_for_each_descendant_pre(blkg, pos_css,
> -				     blkiolat->rqos.disk->queue->root_blkg) {
> +				     blkiolat->rqos.disk->root_blkg) {
>  		struct iolatency_grp *iolat;
>  		struct child_latency_info *lat_info;
>  		unsigned long flags;
> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
> index 74bb1e753ea09d..902203bdddb4b4 100644
> --- a/block/blk-throttle.c
> +++ b/block/blk-throttle.c
> @@ -451,7 +451,8 @@ static void blk_throtl_update_limit_valid(struct throtl_data *td)
>  	bool low_valid = false;
>  
>  	rcu_read_lock();
> -	blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) {
> +	blkg_for_each_descendant_post(blkg, pos_css,
> +			td->queue->disk->root_blkg) {
>  		struct throtl_grp *tg = blkg_to_tg(blkg);
>  
>  		if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] ||
> @@ -1180,7 +1181,7 @@ static void throtl_pending_timer_fn(struct timer_list *t)
>  
>  	spin_lock_irq(&q->queue_lock);
>  
> -	if (!q->root_blkg)
> +	if (!q->disk->root_blkg)
>  		goto out_unlock;
>  
>  	if (throtl_can_upgrade(td, NULL))
> @@ -1322,7 +1323,8 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global)
>  	 * blk-throttle.
>  	 */
>  	blkg_for_each_descendant_pre(blkg, pos_css,
> -			global ? tg->td->queue->root_blkg : tg_to_blkg(tg)) {
> +			global ? tg->td->queue->disk->root_blkg :
> +			tg_to_blkg(tg)) {
>  		struct throtl_grp *this_tg = blkg_to_tg(blkg);
>  		struct throtl_grp *parent_tg;
>  
> @@ -1717,7 +1719,7 @@ void blk_throtl_cancel_bios(struct gendisk *disk)
>  	 * path need RCU protection and to prevent warning from lockdep.
>  	 */
>  	rcu_read_lock();
> -	blkg_for_each_descendant_post(blkg, pos_css, q->root_blkg) {
> +	blkg_for_each_descendant_post(blkg, pos_css, disk->root_blkg) {
>  		struct throtl_grp *tg = blkg_to_tg(blkg);
>  		struct throtl_service_queue *sq = &tg->service_queue;
>  
> @@ -1871,7 +1873,8 @@ static bool throtl_can_upgrade(struct throtl_data *td,
>  		return false;
>  
>  	rcu_read_lock();
> -	blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) {
> +	blkg_for_each_descendant_post(blkg, pos_css,
> +			td->queue->disk->root_blkg) {
>  		struct throtl_grp *tg = blkg_to_tg(blkg);
>  
>  		if (tg == this_tg)
> @@ -1917,7 +1920,8 @@ static void throtl_upgrade_state(struct throtl_data *td)
>  	td->low_upgrade_time = jiffies;
>  	td->scale = 0;
>  	rcu_read_lock();
> -	blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) {
> +	blkg_for_each_descendant_post(blkg, pos_css,
> +			td->queue->disk->root_blkg) {
>  		struct throtl_grp *tg = blkg_to_tg(blkg);
>  		struct throtl_service_queue *sq = &tg->service_queue;
>  
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index b87ed829ab9418..d27010c25f75f0 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -163,6 +163,11 @@ struct gendisk {
>  	struct timer_rand_state *random;
>  	atomic_t sync_io;		/* RAID */
>  	struct disk_events *ev;
> +#ifdef CONFIG_BLK_CGROUP
> +	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
> +	struct blkcg_gq		*root_blkg;
> +	struct list_head	blkg_list;
> +#endif
>  #ifdef  CONFIG_BLK_DEV_INTEGRITY
>  	struct kobject integrity_kobj;
>  #endif	/* CONFIG_BLK_DEV_INTEGRITY */
> @@ -481,11 +486,6 @@ struct request_queue {
>  	struct blk_mq_tags	*sched_shared_tags;
>  
>  	struct list_head	icq_list;
> -#ifdef CONFIG_BLK_CGROUP
> -	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
> -	struct blkcg_gq		*root_blkg;
> -	struct list_head	blkg_list;
> -#endif
>  
>  	struct queue_limits	limits;
>  
> -- 
> 2.39.0
> 

-- 
Regards,
Andreas

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