blk-cgroup: remove unneeded includes from <linux/blk-cgroup.h>

Remove all the includes that aren't actually needed from
<linux/blk-cgroup.h> and push them to the actual source files where
needed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-12-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-cgroup.h

@@ -15,6 +15,8 @@
  */
 
 #include <linux/blk-cgroup.h>
+#include <linux/cgroup.h>
+#include <linux/kthread.h>
 #include <linux/blk-mq.h>
 
 struct blkcg_gq;

include/linux/blk-cgroup.h

@@ -14,16 +14,11 @@
  * 	              Nauman Rafique <nauman@google.com>
  */
 
-#include <linux/cgroup.h>
-#include <linux/percpu.h>
-#include <linux/percpu_counter.h>
-#include <linux/u64_stats_sync.h>
-#include <linux/seq_file.h>
-#include <linux/radix-tree.h>
-#include <linux/blkdev.h>
-#include <linux/atomic.h>
-#include <linux/kthread.h>
-#include <linux/fs.h>
+#include <linux/types.h>
+
+struct bio;
+struct cgroup_subsys_state;
+struct request_queue;
 
 #define FC_APPID_LEN              129
 

mm/backing-dev.c

 // SPDX-License-Identifier: GPL-2.0-only
 
+#include <linux/blkdev.h>
 #include <linux/wait.h>
 #include <linux/rbtree.h>
 #include <linux/kthread.h>

mm/readahead.c

@@ -113,6 +113,7 @@
  * ->readpage() which may be less efficient.
  */
 
+#include <linux/blkdev.h>
 #include <linux/kernel.h>
 #include <linux/dax.h>
 #include <linux/gfp.h>

mm/swapfile.c

@@ -6,6 +6,7 @@
  *  Swap reorganised 29.12.95, Stephen Tweedie
  */
 
+#include <linux/blkdev.h>
 #include <linux/mm.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/task.h>