writeback: remove struct bdi_writeback_congested

We never set any congested bits in the group writeback instances of it.
And for the simpler bdi-wide case a simple scalar field is all that
that is needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 2 insertions, 47 deletions

diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index cc5aa1f32b91..1cec4521e1fb 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -88,26 +88,6 @@ struct wb_completion {
 	struct wb_completion cmpl = WB_COMPLETION_INIT(bdi)
 
 /*
- * For cgroup writeback, multiple wb's may map to the same blkcg.  Those
- * wb's can operate mostly independently but should share the congested
- * state.  To facilitate such sharing, the congested state is tracked using
- * the following struct which is created on demand, indexed by blkcg ID on
- * its bdi, and refcounted.
- */
-struct bdi_writeback_congested {
-	unsigned long state;		/* WB_[a]sync_congested flags */
-	refcount_t refcnt;		/* nr of attached wb's and blkg */
-
-#ifdef CONFIG_CGROUP_WRITEBACK
-	struct backing_dev_info *__bdi;	/* the associated bdi, set to NULL
-					 * on bdi unregistration. For memcg-wb
-					 * internal use only! */
-	int blkcg_id;			/* ID of the associated blkcg */
-	struct rb_node rb_node;		/* on bdi->cgwb_congestion_tree */
-#endif
-};
-
-/*
  * Each wb (bdi_writeback) can perform writeback operations, is measured
  * and throttled, independently.  Without cgroup writeback, each bdi
  * (bdi_writeback) is served by its embedded bdi->wb.
@@ -140,7 +120,7 @@ struct bdi_writeback {
 
 	struct percpu_counter stat[NR_WB_STAT_ITEMS];
 
-	struct bdi_writeback_congested *congested;
+	unsigned long congested;	/* WB_[a]sync_congested flags */
 
 	unsigned long bw_time_stamp;	/* last time write bw is updated */
 	unsigned long dirtied_stamp;
@@ -208,11 +188,8 @@ struct backing_dev_info {
 	struct list_head wb_list; /* list of all wbs */
 #ifdef CONFIG_CGROUP_WRITEBACK
 	struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */
-	struct rb_root cgwb_congested_tree; /* their congested states */
 	struct mutex cgwb_release_mutex;  /* protect shutdown of wb structs */
 	struct rw_semaphore wb_switch_rwsem; /* no cgwb switch while syncing */
-#else
-	struct bdi_writeback_congested *wb_congested;
 #endif
 	wait_queue_head_t wb_waitq;
 
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 6b3504bf7a42..9173d2c22b4a 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -173,7 +173,7 @@ static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
 
 	if (bdi->congested_fn)
 		return bdi->congested_fn(bdi->congested_data, cong_bits);
-	return wb->congested->state & cong_bits;
+	return wb->congested & cong_bits;
 }
 
 long congestion_wait(int sync, long timeout);
@@ -224,9 +224,6 @@ static inline int bdi_sched_wait(void *word)
 
 #ifdef CONFIG_CGROUP_WRITEBACK
 
-struct bdi_writeback_congested *
-wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
-void wb_congested_put(struct bdi_writeback_congested *congested);
 struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi,
 				    struct cgroup_subsys_state *memcg_css);
 struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
@@ -404,19 +401,6 @@ static inline bool inode_cgwb_enabled(struct inode *inode)
 	return false;
 }
 
-static inline struct bdi_writeback_congested *
-wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
-{
-	refcount_inc(&bdi->wb_congested->refcnt);
-	return bdi->wb_congested;
-}
-
-static inline void wb_congested_put(struct bdi_writeback_congested *congested)
-{
-	if (refcount_dec_and_test(&congested->refcnt))
-		kfree(congested);
-}
-
 static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
 {
 	return &bdi->wb;
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 431b2d18bf40..c8fc9792ac77 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -109,12 +109,6 @@ struct blkcg_gq {
 	struct hlist_node		blkcg_node;
 	struct blkcg			*blkcg;
 
-	/*
-	 * Each blkg gets congested separately and the congestion state is
-	 * propagated to the matching bdi_writeback_congested.
-	 */
-	struct bdi_writeback_congested	*wb_congested;
-
 	/* all non-root blkcg_gq's are guaranteed to have access to parent */
 	struct blkcg_gq			*parent;