blk-cgroup: pin the gendisk in struct blkcg_gq

Currently each blkcg_gq holds a request_queue reference, which is what
is used in the policies.  But a lot of these interfaces will move over to
use a gendisk, so store a disk in struct blkcg_gq and hold a reference to
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index b42956a..1d4a3f1 100644 (file)
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -405,7 +405,7 @@ static void bfqg_stats_xfer_dead(struct bfq_group *bfqg)
 
        parent = bfqg_parent(bfqg);
 
-       lockdep_assert_held(&bfqg_to_blkg(bfqg)->q->queue_lock);
+       lockdep_assert_held(&bfqg_to_blkg(bfqg)->disk->queue->queue_lock);
 
        if (unlikely(!parent))
                return;
@@ -536,7 +536,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd)
 {
        struct blkcg_gq *blkg = pd_to_blkg(pd);
        struct bfq_group *bfqg = blkg_to_bfqg(blkg);
-       struct bfq_data *bfqd = blkg->q->elevator->elevator_data;
+       struct bfq_data *bfqd = blkg->disk->queue->elevator->elevator_data;
        struct bfq_entity *entity = &bfqg->entity;
        struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg);
 
@@ -1201,7 +1201,7 @@ static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
        struct cgroup_subsys_state *pos_css;
        u64 sum = 0;
 
-       lockdep_assert_held(&blkg->q->queue_lock);
+       lockdep_assert_held(&blkg->disk->queue->queue_lock);
 
        rcu_read_lock();
        blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {

diff --git a/block/blk-cgroup-rwstat.c b/block/blk-cgroup-rwstat.c
index 3304e84..b8b8c82 100644 (file)
--- a/block/blk-cgroup-rwstat.c
+++ b/block/blk-cgroup-rwstat.c
@@ -107,7 +107,7 @@ void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
        struct cgroup_subsys_state *pos_css;
        unsigned int i;
 
-       lockdep_assert_held(&blkg->q->queue_lock);
+       lockdep_assert_held(&blkg->disk->queue->queue_lock);
 
        memset(sum, 0, sizeof(*sum));
        rcu_read_lock();

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 0b3226c..0e36838 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -116,7 +116,6 @@ static bool blkcg_policy_enabled(struct request_queue *q,
 
 static void blkg_free(struct blkcg_gq *blkg)
 {
-       struct request_queue *q = blkg->q;
        int i;
 
        /*
@@ -126,16 +125,16 @@ static void blkg_free(struct blkcg_gq *blkg)
         * blkcg_mutex is used to synchronize blkg_free_workfn() and
         * blkcg_deactivate_policy().
         */
-       mutex_lock(&q->blkcg_mutex);
+       mutex_lock(&blkg->disk->queue->blkcg_mutex);
        for (i = 0; i < BLKCG_MAX_POLS; i++)
                if (blkg->pd[i])
                        blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
        if (blkg->parent)
                blkg_put(blkg->parent);
        list_del_init(&blkg->q_node);
-       mutex_unlock(&q->blkcg_mutex);
+       mutex_unlock(&blkg->disk->queue->blkcg_mutex);
 
-       blk_put_queue(q);
+       put_disk(blkg->disk);
        free_percpu(blkg->iostat_cpu);
        percpu_ref_exit(&blkg->refcnt);
        kfree(blkg);
@@ -251,10 +250,12 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk,
        blkg->iostat_cpu = alloc_percpu_gfp(struct blkg_iostat_set, gfp_mask);
        if (!blkg->iostat_cpu)
                goto out_exit_refcnt;
-       if (!blk_get_queue(disk->queue))
+
+       if (test_bit(GD_DEAD, &disk->state))
                goto out_free_iostat;
+       get_device(disk_to_dev(disk));
+       blkg->disk = disk;
 
-       blkg->q = disk->queue;
        INIT_LIST_HEAD(&blkg->q_node);
        spin_lock_init(&blkg->async_bio_lock);
        bio_list_init(&blkg->async_bios);
@@ -290,7 +291,7 @@ out_free_pds:
        while (--i >= 0)
                if (blkg->pd[i])
                        blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
-       blk_put_queue(disk->queue);
+       put_disk(blkg->disk);
 out_free_iostat:
        free_percpu(blkg->iostat_cpu);
 out_exit_refcnt:
@@ -461,7 +462,7 @@ static void blkg_destroy(struct blkcg_gq *blkg)
        struct blkcg *blkcg = blkg->blkcg;
        int i;
 
-       lockdep_assert_held(&blkg->q->queue_lock);
+       lockdep_assert_held(&blkg->disk->queue->queue_lock);
        lockdep_assert_held(&blkcg->lock);
 
        /*
@@ -485,7 +486,7 @@ static void blkg_destroy(struct blkcg_gq *blkg)
 
        blkg->online = false;
 
-       radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
+       radix_tree_delete(&blkcg->blkg_tree, blkg->disk->queue->id);
        hlist_del_init_rcu(&blkg->blkcg_node);
 
        /*
@@ -572,9 +573,7 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css,
 
 const char *blkg_dev_name(struct blkcg_gq *blkg)
 {
-       if (!blkg->q->disk)
-               return NULL;
-       return bdi_dev_name(blkg->q->disk->bdi);
+       return bdi_dev_name(blkg->disk->bdi);
 }
 
 /**
@@ -606,10 +605,10 @@ 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->q->queue_lock);
-               if (blkcg_policy_enabled(blkg->q, pol))
+               spin_lock_irq(&blkg->disk->queue->queue_lock);
+               if (blkcg_policy_enabled(blkg->disk->queue, pol))
                        total += prfill(sf, blkg->pd[pol->plid], data);
-               spin_unlock_irq(&blkg->q->queue_lock);
+               spin_unlock_irq(&blkg->disk->queue->queue_lock);
        }
        rcu_read_unlock();
 
@@ -1033,9 +1032,9 @@ static int blkcg_print_stat(struct seq_file *sf, void *v)
 
        rcu_read_lock();
        hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
-               spin_lock_irq(&blkg->q->queue_lock);
+               spin_lock_irq(&blkg->disk->queue->queue_lock);
                blkcg_print_one_stat(blkg, sf);
-               spin_unlock_irq(&blkg->q->queue_lock);
+               spin_unlock_irq(&blkg->disk->queue->queue_lock);
        }
        rcu_read_unlock();
        return 0;
@@ -1105,7 +1104,7 @@ static void blkcg_destroy_blkgs(struct blkcg *blkcg)
        while (!hlist_empty(&blkcg->blkg_list)) {
                struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first,
                                                struct blkcg_gq, blkcg_node);
-               struct request_queue *q = blkg->q;
+               struct request_queue *q = blkg->disk->queue;
 
                if (need_resched() || !spin_trylock(&q->queue_lock)) {
                        /*

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index b13ee84..996572a 100644 (file)
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -53,8 +53,7 @@ struct blkg_iostat_set {
 
 /* association between a blk cgroup and a request queue */
 struct blkcg_gq {
-       /* Pointer to the associated request_queue */
-       struct request_queue            *q;
+       struct gendisk                  *disk;
        struct list_head                q_node;
        struct hlist_node               blkcg_node;
        struct blkcg                    *blkcg;
@@ -255,11 +254,11 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
                return q->root_blkg;
 
        blkg = rcu_dereference(blkcg->blkg_hint);
-       if (blkg && blkg->q == q)
+       if (blkg && blkg->disk->queue == q)
                return blkg;
 
        blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
-       if (blkg && blkg->q != q)
+       if (blkg && blkg->disk->queue != q)
                blkg = NULL;
        return blkg;
 }
@@ -359,7 +358,7 @@ static inline void blkg_put(struct blkcg_gq *blkg)
 #define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg)          \
        css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css)   \
                if (((d_blkg) = blkg_lookup(css_to_blkcg(pos_css),      \
-                                           (p_blkg)->q)))
+                                           (p_blkg)->disk->queue)))
 
 /**
  * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
@@ -374,7 +373,7 @@ static inline void blkg_put(struct blkcg_gq *blkg)
 #define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg)         \
        css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css)  \
                if (((d_blkg) = blkg_lookup(css_to_blkcg(pos_css),      \
-                                           (p_blkg)->q)))
+                                           (p_blkg)->disk->queue)))
 
 bool __blkcg_punt_bio_submit(struct bio *bio);
 

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 9694394..a2b4e71 100644 (file)
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2953,7 +2953,7 @@ static void ioc_pd_init(struct blkg_policy_data *pd)
 {
        struct ioc_gq *iocg = pd_to_iocg(pd);
        struct blkcg_gq *blkg = pd_to_blkg(&iocg->pd);
-       struct ioc *ioc = q_to_ioc(blkg->q);
+       struct ioc *ioc = q_to_ioc(blkg->disk->queue);
        struct ioc_now now;
        struct blkcg_gq *tblkg;
        unsigned long flags;

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index ecdc107..b55eac2 100644 (file)
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -974,12 +974,12 @@ static void iolatency_pd_init(struct blkg_policy_data *pd)
 {
        struct iolatency_grp *iolat = pd_to_lat(pd);
        struct blkcg_gq *blkg = lat_to_blkg(iolat);
-       struct rq_qos *rqos = blkcg_rq_qos(blkg->q);
+       struct rq_qos *rqos = blkcg_rq_qos(blkg->disk->queue);
        struct blk_iolatency *blkiolat = BLKIOLATENCY(rqos);
        u64 now = ktime_to_ns(ktime_get());
        int cpu;
 
-       if (blk_queue_nonrot(blkg->q))
+       if (blk_queue_nonrot(blkg->disk->queue))
                iolat->ssd = true;
        else
                iolat->ssd = false;

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 6fb5a2f..f802d8f 100644 (file)
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -388,7 +388,7 @@ static void throtl_pd_init(struct blkg_policy_data *pd)
 {
        struct throtl_grp *tg = pd_to_tg(pd);
        struct blkcg_gq *blkg = tg_to_blkg(tg);
-       struct throtl_data *td = blkg->q->td;
+       struct throtl_data *td = blkg->disk->queue->td;
        struct throtl_service_queue *sq = &tg->service_queue;
 
        /*
@@ -1175,7 +1175,7 @@ static void throtl_pending_timer_fn(struct timer_list *t)
 
        /* throtl_data may be gone, so figure out request queue by blkg */
        if (tg)
-               q = tg->pd.blkg->q;
+               q = tg->pd.blkg->disk->queue;
        else
                q = td->queue;