[PATCH 7/7] blkcg: make blkcg_policy methods take a pointer to blkcg_policy_data

From: Tejun Heo
Date: Tue Jul 07 2015 - 11:53:48 EST


The newly added ->pd_alloc_fn() and ->pd_free_fn() deal with pd
(blkg_policy_data) while the older ones use blkg (blkcg_gq). As using
blkg doesn't make sense for ->pd_alloc_fn() and after allocation pd
can always be mapped to blkg and given that these are policy-specific
methods, it makes sense to converge on pd.

This patch makes all methods deal with pd instead of blkg. Most
conversions are trivial. In blk-cgroup.c, a couple method invocation
sites now test whether pd exists instead of policy state for
consistency. This shouldn't cause any behavioral differences.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
block/blk-cgroup.c | 18 ++++++++----------
block/blk-throttle.c | 13 +++++++------
block/cfq-iosched.c | 14 +++++++-------
include/linux/blk-cgroup.h | 8 ++++----
4 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 9180735..92c2a96 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -232,7 +232,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
struct blkcg_policy *pol = blkcg_policy[i];

if (blkg->pd[i] && pol->pd_init_fn)
- pol->pd_init_fn(blkg);
+ pol->pd_init_fn(blkg->pd[i]);
}

/* insert */
@@ -246,7 +246,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
struct blkcg_policy *pol = blkcg_policy[i];

if (blkg->pd[i] && pol->pd_online_fn)
- pol->pd_online_fn(blkg);
+ pol->pd_online_fn(blkg->pd[i]);
}
}
blkg->online = true;
@@ -337,7 +337,7 @@ static void blkg_destroy(struct blkcg_gq *blkg)
struct blkcg_policy *pol = blkcg_policy[i];

if (blkg->pd[i] && pol->pd_offline_fn)
- pol->pd_offline_fn(blkg);
+ pol->pd_offline_fn(blkg->pd[i]);
}
blkg->online = false;

@@ -471,9 +471,8 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css,
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];

- if (blkcg_policy_enabled(blkg->q, pol) &&
- pol->pd_reset_stats_fn)
- pol->pd_reset_stats_fn(blkg);
+ if (blkg->pd[i] && pol->pd_reset_stats_fn)
+ pol->pd_reset_stats_fn(blkg->pd[i]);
}
}

@@ -1105,7 +1104,7 @@ int blkcg_activate_policy(struct request_queue *q,
pd->blkg = blkg;
pd->plid = pol->plid;
if (pol->pd_init_fn)
- pol->pd_init_fn(blkg);
+ pol->pd_init_fn(pd);

spin_unlock(&blkg->blkcg->lock);
}
@@ -1149,10 +1148,9 @@ void blkcg_deactivate_policy(struct request_queue *q,
/* grab blkcg lock too while removing @pd from @blkg */
spin_lock(&blkg->blkcg->lock);

- if (pol->pd_offline_fn)
- pol->pd_offline_fn(blkg);
-
if (blkg->pd[pol->plid]) {
+ if (pol->pd_offline_fn)
+ pol->pd_offline_fn(blkg->pd[pol->plid]);
pol->pd_free_fn(blkg->pd[pol->plid]);
blkg->pd[pol->plid] = NULL;
}
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index c3a235b..c2c7547 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -377,9 +377,10 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
return &tg->pd;
}

-static void throtl_pd_init(struct blkcg_gq *blkg)
+static void throtl_pd_init(struct blkg_policy_data *pd)
{
- struct throtl_grp *tg = blkg_to_tg(blkg);
+ 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_service_queue *sq = &tg->service_queue;

@@ -417,13 +418,13 @@ static void tg_update_has_rules(struct throtl_grp *tg)
(tg->bps[rw] != -1 || tg->iops[rw] != -1);
}

-static void throtl_pd_online(struct blkcg_gq *blkg)
+static void throtl_pd_online(struct blkg_policy_data *pd)
{
/*
* We don't want new groups to escape the limits of its ancestors.
* Update has_rules[] after a new group is brought online.
*/
- tg_update_has_rules(blkg_to_tg(blkg));
+ tg_update_has_rules(pd_to_tg(pd));
}

static void throtl_pd_free(struct blkg_policy_data *pd)
@@ -435,9 +436,9 @@ static void throtl_pd_free(struct blkg_policy_data *pd)
kfree(tg);
}

-static void throtl_pd_reset_stats(struct blkcg_gq *blkg)
+static void throtl_pd_reset_stats(struct blkg_policy_data *pd)
{
- struct throtl_grp *tg = blkg_to_tg(blkg);
+ struct throtl_grp *tg = pd_to_tg(pd);
int cpu;

for_each_possible_cpu(cpu) {
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 4b795c7..95e6b0c 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1597,18 +1597,18 @@ static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node)
return &cfqg->pd;
}

-static void cfq_pd_init(struct blkcg_gq *blkg)
+static void cfq_pd_init(struct blkg_policy_data *pd)
{
- struct cfq_group *cfqg = blkg_to_cfqg(blkg);
- struct cfq_group_data *cgd = blkcg_to_cfqgd(blkg->blkcg);
+ struct cfq_group *cfqg = pd_to_cfqg(pd);
+ struct cfq_group_data *cgd = blkcg_to_cfqgd(pd->blkg->blkcg);

cfqg->weight = cgd->weight;
cfqg->leaf_weight = cgd->leaf_weight;
}

-static void cfq_pd_offline(struct blkcg_gq *blkg)
+static void cfq_pd_offline(struct blkg_policy_data *pd)
{
- struct cfq_group *cfqg = blkg_to_cfqg(blkg);
+ struct cfq_group *cfqg = pd_to_cfqg(pd);
int i;

for (i = 0; i < IOPRIO_BE_NR; i++) {
@@ -1661,9 +1661,9 @@ static struct blkg_rwstat cfqg_rwstat_pd_recursive_sum(struct blkg_policy_data *
return a;
}

-static void cfq_pd_reset_stats(struct blkcg_gq *blkg)
+static void cfq_pd_reset_stats(struct blkg_policy_data *pd)
{
- struct cfq_group *cfqg = blkg_to_cfqg(blkg);
+ struct cfq_group *cfqg = pd_to_cfqg(pd);

cfqg_stats_reset(&cfqg->stats);
cfqg_stats_reset(&cfqg->dead_stats);
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 06c0297..2db2c62 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -133,11 +133,11 @@ struct blkcg_gq {

typedef void (blkcg_pol_init_cpd_fn)(const struct blkcg *blkcg);
typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
-typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
-typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
-typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
-typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);

struct blkcg_policy {
int plid;
--
2.4.3

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