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-rw-r--r--block/blk-cgroup.h60
1 files changed, 34 insertions, 26 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index a443b84..18b021e 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -59,16 +59,25 @@ struct blkg_rwstat {
uint64_t cnt[BLKG_RWSTAT_NR];
};
-/* per-blkg per-policy data */
+/*
+ * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
+ * request_queue (q). This is used by blkcg policies which need to track
+ * information per blkcg - q pair.
+ *
+ * There can be multiple active blkcg policies and each has its private
+ * data on each blkg, the size of which is determined by
+ * blkcg_policy->pd_size. blkcg core allocates and frees such areas
+ * together with blkg and invokes pd_init/exit_fn() methods.
+ *
+ * Such private data must embed struct blkg_policy_data (pd) at the
+ * beginning and pd_size can't be smaller than pd.
+ */
struct blkg_policy_data {
/* the blkg this per-policy data belongs to */
struct blkcg_gq *blkg;
/* used during policy activation */
struct list_head alloc_node;
-
- /* pol->pdata_size bytes of private data used by policy impl */
- char pdata[] __aligned(__alignof__(unsigned long long));
};
/* association between a blk cgroup and a request queue */
@@ -100,7 +109,7 @@ struct blkcg_policy {
struct blkcg_policy_ops ops;
int plid;
/* policy specific private data size */
- size_t pdata_size;
+ size_t pd_size;
/* cgroup files for the policy */
struct cftype *cftypes;
};
@@ -125,14 +134,16 @@ void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol);
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
- u64 (*prfill)(struct seq_file *, void *, int),
+ u64 (*prfill)(struct seq_file *,
+ struct blkg_policy_data *, int),
const struct blkcg_policy *pol, int data,
bool show_total);
-u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v);
-u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
+u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
+u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
const struct blkg_rwstat *rwstat);
-u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off);
-u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, int off);
+u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
+u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off);
struct blkg_conf_ctx {
struct gendisk *disk;
@@ -152,26 +163,21 @@ void blkg_conf_finish(struct blkg_conf_ctx *ctx);
*
* Return pointer to private data associated with the @blkg-@pol pair.
*/
-static inline void *blkg_to_pdata(struct blkcg_gq *blkg,
- struct blkcg_policy *pol)
+static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
+ struct blkcg_policy *pol)
{
- return blkg ? blkg->pd[pol->plid]->pdata : NULL;
+ return blkg ? blkg->pd[pol->plid] : NULL;
}
/**
* pdata_to_blkg - get blkg associated with policy private data
- * @pdata: policy private data of interest
+ * @pd: policy private data of interest
*
- * @pdata is policy private data. Determine the blkg it's associated with.
+ * @pd is policy private data. Determine the blkg it's associated with.
*/
-static inline struct blkcg_gq *pdata_to_blkg(void *pdata)
+static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
{
- if (pdata) {
- struct blkg_policy_data *pd =
- container_of(pdata, struct blkg_policy_data, pdata);
- return pd->blkg;
- }
- return NULL;
+ return pd ? pd->blkg : NULL;
}
/**
@@ -342,6 +348,9 @@ static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
struct cgroup;
+struct blkg_policy_data {
+};
+
struct blkcg_gq {
};
@@ -361,10 +370,9 @@ static inline int blkcg_activate_policy(struct request_queue *q,
static inline void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol) { }
-static inline void *blkg_to_pdata(struct blkcg_gq *blkg,
- struct blkcg_policy *pol) { return NULL; }
-static inline struct blkcg_gq *pdata_to_blkg(void *pdata,
- struct blkcg_policy *pol) { return NULL; }
+static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
+ struct blkcg_policy *pol) { return NULL; }
+static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
static inline void blkg_get(struct blkcg_gq *blkg) { }
static inline void blkg_put(struct blkcg_gq *blkg) { }
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