blkcg: move blkio_group_conf->weight to cfq

blkio_group_conf->weight is owned by cfq and has no reason to be
defined in blkcg core.  Replace it with cfq_group->dev_weight and let
conf setting functions directly set it.  If dev_weight is zero, the
cfqg doesn't have device specific weight configured.

Also, rename BLKIO_WEIGHT_* constants to CFQ_WEIGHT_* and rename
blkio_cgroup->weight to blkio_cgroup->cfq_weight.  We eventually want
per-policy storage in blkio_cgroup but just mark the ownership of the
field for now.

Signed-off-by: Tejun Heo <tj@kernel.org>

3 files changed, 45 insertions, 50 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 16f6ee65a593..c0e239b8455e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -30,7 +30,7 @@ static LIST_HEAD(blkio_list);
 static DEFINE_MUTEX(all_q_mutex);
 static LIST_HEAD(all_q_list);
 
-struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
+struct blkio_cgroup blkio_root_cgroup = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT };
 EXPORT_SYMBOL_GPL(blkio_root_cgroup);
 
 static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES];
@@ -611,7 +611,7 @@ static struct cgroup_subsys_state *blkiocg_create(struct cgroup *cgroup)
         if (!blkcg)
                 return ERR_PTR(-ENOMEM);
 
-        blkcg->weight = BLKIO_WEIGHT_DEFAULT;
+        blkcg->cfq_weight = CFQ_WEIGHT_DEFAULT;
         blkcg->id = atomic64_inc_return(&id_seq); /* root is 0, start from 1 */
 done:
         spin_lock_init(&blkcg->lock);
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index e368dd00b8cf..386db2974a08 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -29,6 +29,11 @@ enum blkio_policy_id {
 
 #ifdef CONFIG_BLK_CGROUP
 
+/* CFQ specific, out here for blkcg->cfq_weight */
+#define CFQ_WEIGHT_MIN          10
+#define CFQ_WEIGHT_MAX          1000
+#define CFQ_WEIGHT_DEFAULT      500
+
 /* cft->private [un]packing for stat printing */
 #define BLKCG_STAT_PRIV(pol, off)       (((unsigned)(pol) << 16) | (off))
 #define BLKCG_STAT_POL(prv)             ((unsigned)(prv) >> 16)
@@ -46,12 +51,14 @@ enum blkg_rwstat_type {
 
 struct blkio_cgroup {
         struct cgroup_subsys_state css;
-        unsigned int weight;
         spinlock_t lock;
         struct hlist_head blkg_list;
 
         /* for policies to test whether associated blkcg has changed */
         uint64_t id;
+
+        /* TODO: per-policy storage in blkio_cgroup */
+        unsigned int cfq_weight;        /* belongs to cfq */
 };
 
 struct blkg_stat {
@@ -65,7 +72,6 @@ struct blkg_rwstat {
 };
 
 struct blkio_group_conf {
-        unsigned int weight;
         u64 iops[2];
         u64 bps[2];
 };
@@ -355,10 +361,6 @@ static inline void blkg_put(struct blkio_group *blkg) { }
 
 #endif
 
-#define BLKIO_WEIGHT_MIN        10
-#define BLKIO_WEIGHT_MAX        1000
-#define BLKIO_WEIGHT_DEFAULT    500
-
 #ifdef CONFIG_BLK_CGROUP
 extern struct blkio_cgroup blkio_root_cgroup;
 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a1f37dfd1b8b..adab10de6eea 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -224,7 +224,7 @@ struct cfq_group {
         u64 vdisktime;
         unsigned int weight;
         unsigned int new_weight;
-        bool needs_update;
+        unsigned int dev_weight;
 
         /* number of cfqq currently on this group */
         int nr_cfqq;
@@ -838,7 +838,7 @@ static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg)
 {
         u64 d = delta << CFQ_SERVICE_SHIFT;
 
-        d = d * BLKIO_WEIGHT_DEFAULT;
+        d = d * CFQ_WEIGHT_DEFAULT;
         do_div(d, cfqg->weight);
         return d;
 }
@@ -1165,9 +1165,9 @@ static void
 cfq_update_group_weight(struct cfq_group *cfqg)
 {
         BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
-        if (cfqg->needs_update) {
+        if (cfqg->new_weight) {
                 cfqg->weight = cfqg->new_weight;
-                cfqg->needs_update = false;
+                cfqg->new_weight = 0;
         }
 }
 
@@ -1325,21 +1325,12 @@ static void cfq_init_cfqg_base(struct cfq_group *cfqg)
 }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void cfq_update_blkio_group_weight(struct blkio_group *blkg,
-                                          unsigned int weight)
-{
-        struct cfq_group *cfqg = blkg_to_cfqg(blkg);
-
-        cfqg->new_weight = weight;
-        cfqg->needs_update = true;
-}
-
 static void cfq_init_blkio_group(struct blkio_group *blkg)
 {
         struct cfq_group *cfqg = blkg_to_cfqg(blkg);
 
         cfq_init_cfqg_base(cfqg);
-        cfqg->weight = blkg->blkcg->weight;
+        cfqg->weight = blkg->blkcg->cfq_weight;
 }
 
 /*
@@ -1377,36 +1368,38 @@ static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
         cfqg_get(cfqg);
 }
 
-static u64 blkg_prfill_weight_device(struct seq_file *sf,
+static u64 cfqg_prfill_weight_device(struct seq_file *sf,
                                      struct blkg_policy_data *pd, int off)
 {
-        if (!pd->conf.weight)
+        struct cfq_group *cfqg = (void *)pd->pdata;
+
+        if (!cfqg->dev_weight)
                 return 0;
-        return __blkg_prfill_u64(sf, pd, pd->conf.weight);
+        return __blkg_prfill_u64(sf, pd, cfqg->dev_weight);
 }
 
-static int blkcg_print_weight_device(struct cgroup *cgrp, struct cftype *cft,
-                                     struct seq_file *sf)
+static int cfqg_print_weight_device(struct cgroup *cgrp, struct cftype *cft,
+                                    struct seq_file *sf)
 {
         blkcg_print_blkgs(sf, cgroup_to_blkio_cgroup(cgrp),
-                          blkg_prfill_weight_device, BLKIO_POLICY_PROP, 0,
+                          cfqg_prfill_weight_device, BLKIO_POLICY_PROP, 0,
                           false);
         return 0;
 }
 
-static int blkcg_print_weight(struct cgroup *cgrp, struct cftype *cft,
-                              struct seq_file *sf)
+static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft,
+                            struct seq_file *sf)
 {
-        seq_printf(sf, "%u\n", cgroup_to_blkio_cgroup(cgrp)->weight);
+        seq_printf(sf, "%u\n", cgroup_to_blkio_cgroup(cgrp)->cfq_weight);
         return 0;
 }
 
-static int blkcg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
-                                   const char *buf)
+static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
+                                  const char *buf)
 {
         struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
-        struct blkg_policy_data *pd;
         struct blkg_conf_ctx ctx;
+        struct cfq_group *cfqg;
         int ret;
 
         ret = blkg_conf_prep(blkcg, buf, &ctx);
@@ -1414,11 +1407,11 @@ static int blkcg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
                 return ret;
 
         ret = -EINVAL;
-        pd = ctx.blkg->pd[BLKIO_POLICY_PROP];
-        if (pd && (!ctx.v || (ctx.v >= BLKIO_WEIGHT_MIN &&
-                              ctx.v <= BLKIO_WEIGHT_MAX))) {
-                pd->conf.weight = ctx.v;
-                cfq_update_blkio_group_weight(ctx.blkg, ctx.v ?: blkcg->weight);
+        cfqg = blkg_to_cfqg(ctx.blkg);
+        if (cfqg && (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN &&
+                                ctx.v <= CFQ_WEIGHT_MAX))) {
+                cfqg->dev_weight = ctx.v;
+                cfqg->new_weight = cfqg->dev_weight ?: blkcg->cfq_weight;
                 ret = 0;
         }
 
@@ -1426,23 +1419,23 @@ static int blkcg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
         return ret;
 }
 
-static int blkcg_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
+static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
 {
         struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
         struct blkio_group *blkg;
         struct hlist_node *n;
 
-        if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
+        if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX)
                 return -EINVAL;
 
         spin_lock_irq(&blkcg->lock);
-        blkcg->weight = (unsigned int)val;
+        blkcg->cfq_weight = (unsigned int)val;
 
         hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
-                struct blkg_policy_data *pd = blkg->pd[BLKIO_POLICY_PROP];
+                struct cfq_group *cfqg = blkg_to_cfqg(blkg);
 
-                if (pd && !pd->conf.weight)
-                        cfq_update_blkio_group_weight(blkg, blkcg->weight);
+                if (cfqg && !cfqg->dev_weight)
+                        cfqg->new_weight = blkcg->cfq_weight;
         }
 
         spin_unlock_irq(&blkcg->lock);
@@ -1480,14 +1473,14 @@ static int cfqg_print_avg_queue_size(struct cgroup *cgrp, struct cftype *cft,
 static struct cftype cfq_blkcg_files[] = {
         {
                 .name = "weight_device",
-                .read_seq_string = blkcg_print_weight_device,
-                .write_string = blkcg_set_weight_device,
+                .read_seq_string = cfqg_print_weight_device,
+                .write_string = cfqg_set_weight_device,
                 .max_write_len = 256,
         },
         {
                 .name = "weight",
-                .read_seq_string = blkcg_print_weight,
-                .write_u64 = blkcg_set_weight,
+                .read_seq_string = cfq_print_weight,
+                .write_u64 = cfq_set_weight,
         },
         {
                 .name = "time",
@@ -3983,7 +3976,7 @@ static int cfq_init_queue(struct request_queue *q)
                 return -ENOMEM;
         }
 
-        cfqd->root_group->weight = 2*BLKIO_WEIGHT_DEFAULT;
+        cfqd->root_group->weight = 2 * CFQ_WEIGHT_DEFAULT;
 
         /*
          * Not strictly needed (since RB_ROOT just clears the node and we