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blkcg: minor updates around blkcg_policy_data
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* Rename blkcg->pd[] to blkcg->cpd[] so that cpd is consistently used
  for blkcg_policy_data.

* Make blkcg_policy->cpd_init_fn() take blkcg_policy_data instead of
  blkcg.  This makes it consistent with blkg_policy_data methods and
  to-be-added cpd alloc/free methods.

* blkcg_policy_data->blkcg and cpd_to_blkcg() added so that
  cpd_init_fn() can determine the associated blkcg from
  blkcg_policy_data.

v2: blkcg_policy_data->blkcg initializations were missing.  Added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Tejun Heo authored and Jens Axboe committed Aug 18, 2015
1 parent a9520cd commit 8143764
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Showing 3 changed files with 28 additions and 21 deletions.
24 changes: 13 additions & 11 deletions block/blk-cgroup.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -821,7 +821,7 @@ static void blkcg_css_free(struct cgroup_subsys_state *css)
mutex_unlock(&blkcg_pol_mutex);

for (i = 0; i < BLKCG_MAX_POLS; i++)
kfree(blkcg->pd[i]);
kfree(blkcg->cpd[i]);
kfree(blkcg);
}

Expand Down Expand Up @@ -857,15 +857,16 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
if (!pol || !pol->cpd_size)
continue;

BUG_ON(blkcg->pd[i]);
BUG_ON(blkcg->cpd[i]);
cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
if (!cpd) {
ret = ERR_PTR(-ENOMEM);
goto free_pd_blkcg;
}
blkcg->pd[i] = cpd;
blkcg->cpd[i] = cpd;
cpd->blkcg = blkcg;
cpd->plid = i;
pol->cpd_init_fn(blkcg);
pol->cpd_init_fn(cpd);
}

spin_lock_init(&blkcg->lock);
Expand All @@ -881,7 +882,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)

free_pd_blkcg:
for (i--; i >= 0; i--)
kfree(blkcg->pd[i]);
kfree(blkcg->cpd[i]);
free_blkcg:
kfree(blkcg);
mutex_unlock(&blkcg_pol_mutex);
Expand Down Expand Up @@ -1168,9 +1169,10 @@ int blkcg_policy_register(struct blkcg_policy *pol)
goto err_free_cpds;
}

blkcg->pd[pol->plid] = cpd;
blkcg->cpd[pol->plid] = cpd;
cpd->blkcg = blkcg;
cpd->plid = pol->plid;
pol->cpd_init_fn(blkcg);
pol->cpd_init_fn(cpd);
}
}

Expand All @@ -1186,8 +1188,8 @@ int blkcg_policy_register(struct blkcg_policy *pol)
err_free_cpds:
if (pol->cpd_size) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
kfree(blkcg->pd[pol->plid]);
blkcg->pd[pol->plid] = NULL;
kfree(blkcg->cpd[pol->plid]);
blkcg->cpd[pol->plid] = NULL;
}
}
blkcg_policy[pol->plid] = NULL;
Expand Down Expand Up @@ -1222,8 +1224,8 @@ void blkcg_policy_unregister(struct blkcg_policy *pol)

if (pol->cpd_size) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
kfree(blkcg->pd[pol->plid]);
blkcg->pd[pol->plid] = NULL;
kfree(blkcg->cpd[pol->plid]);
blkcg->cpd[pol->plid] = NULL;
}
}
blkcg_policy[pol->plid] = NULL;
Expand Down
11 changes: 5 additions & 6 deletions block/cfq-iosched.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -220,7 +220,7 @@ struct cfqg_stats {
/* Per-cgroup data */
struct cfq_group_data {
/* must be the first member */
struct blkcg_policy_data pd;
struct blkcg_policy_data cpd;

unsigned int weight;
unsigned int leaf_weight;
Expand Down Expand Up @@ -612,7 +612,7 @@ static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd)
static struct cfq_group_data
*cpd_to_cfqgd(struct blkcg_policy_data *cpd)
{
return cpd ? container_of(cpd, struct cfq_group_data, pd) : NULL;
return cpd ? container_of(cpd, struct cfq_group_data, cpd) : NULL;
}

static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
Expand Down Expand Up @@ -1568,12 +1568,11 @@ static void cfqg_stats_init(struct cfqg_stats *stats)
#endif
}

static void cfq_cpd_init(const struct blkcg *blkcg)
static void cfq_cpd_init(struct blkcg_policy_data *cpd)
{
struct cfq_group_data *cgd =
cpd_to_cfqgd(blkcg->pd[blkcg_policy_cfq.plid]);
struct cfq_group_data *cgd = cpd_to_cfqgd(cpd);

if (blkcg == &blkcg_root) {
if (cpd_to_blkcg(cpd) == &blkcg_root) {
cgd->weight = 2 * CFQ_WEIGHT_DEFAULT;
cgd->leaf_weight = 2 * CFQ_WEIGHT_DEFAULT;
} else {
Expand Down
14 changes: 10 additions & 4 deletions include/linux/blk-cgroup.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@ struct blkcg {
struct blkcg_gq *blkg_hint;
struct hlist_head blkg_list;

struct blkcg_policy_data *pd[BLKCG_MAX_POLS];
struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];

struct list_head all_blkcgs_node;
#ifdef CONFIG_CGROUP_WRITEBACK
Expand Down Expand Up @@ -88,7 +88,8 @@ struct blkg_policy_data {
* each policy handle per-blkcg data.
*/
struct blkcg_policy_data {
/* the policy id this per-policy data belongs to */
/* the blkcg and policy id this per-policy data belongs to */
struct blkcg *blkcg;
int plid;
};

Expand Down Expand Up @@ -123,7 +124,7 @@ struct blkcg_gq {
struct rcu_head rcu_head;
};

typedef void (blkcg_pol_init_cpd_fn)(const struct blkcg *blkcg);
typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
Expand Down Expand Up @@ -243,7 +244,7 @@ static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
struct blkcg_policy *pol)
{
return blkcg ? blkcg->pd[pol->plid] : NULL;
return blkcg ? blkcg->cpd[pol->plid] : NULL;
}

/**
Expand All @@ -257,6 +258,11 @@ static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
return pd ? pd->blkg : NULL;
}

static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
{
return cpd ? cpd->blkcg : NULL;
}

/**
* blkg_path - format cgroup path of blkg
* @blkg: blkg of interest
Expand Down

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