[PATCH] block/laptop_mode: Convert timers to use timer_setup()

[Kees Cook <keescook@chromium.org>]

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: linux-block@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
This requires commit 686fef928bba ("timer: Prepare to change timer
callback argument type") in v4.14-rc3, but should be otherwise
stand-alone.
---
 block/blk-core.c          | 10 +++++-----
 include/linux/writeback.h |  2 +-
 mm/page-writeback.c       |  9 +++++----
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 048be4aa6024..070913294cbb 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -803,9 +803,9 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref)
 	wake_up_all(&q->mq_freeze_wq);
 }
 
-static void blk_rq_timed_out_timer(unsigned long data)
+static void blk_rq_timed_out_timer(struct timer_list *t)
 {
-	struct request_queue *q = (struct request_queue *)data;
+	struct request_queue *q = from_timer(q, t, timeout);
 
 	kblockd_schedule_work(&q->timeout_work);
 }
@@ -841,9 +841,9 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 	q->backing_dev_info->name = "block";
 	q->node = node_id;
 
-	setup_timer(&q->backing_dev_info->laptop_mode_wb_timer,
-		    laptop_mode_timer_fn, (unsigned long) q);
-	setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
+	timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,
+		    laptop_mode_timer_fn, 0);
+	timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
 	INIT_LIST_HEAD(&q->queue_head);
 	INIT_LIST_HEAD(&q->timeout_list);
 	INIT_LIST_HEAD(&q->icq_list);
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index d5815794416c..3bfb50e69a81 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -329,7 +329,7 @@ static inline void cgroup_writeback_umount(void)
 void laptop_io_completion(struct backing_dev_info *info);
 void laptop_sync_completion(void);
 void laptop_mode_sync(struct work_struct *work);
-void laptop_mode_timer_fn(unsigned long data);
+void laptop_mode_timer_fn(struct timer_list *t);
 #else
 static inline void laptop_sync_completion(void) { }
 #endif
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0b9c5cbe8eba..1be0e3067f04 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1977,9 +1977,10 @@ int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
 }
 
 #ifdef CONFIG_BLOCK
-void laptop_mode_timer_fn(unsigned long data)
+void laptop_mode_timer_fn(struct timer_list *t)
 {
-	struct request_queue *q = (struct request_queue *)data;
+	struct backing_dev_info *backing_dev_info =
+		from_timer(backing_dev_info, t, laptop_mode_wb_timer);
 	int nr_pages = global_node_page_state(NR_FILE_DIRTY) +
 		global_node_page_state(NR_UNSTABLE_NFS);
 	struct bdi_writeback *wb;
@@ -1988,11 +1989,11 @@ void laptop_mode_timer_fn(unsigned long data)
 	 * We want to write everything out, not just down to the dirty
 	 * threshold
 	 */
-	if (!bdi_has_dirty_io(q->backing_dev_info))
+	if (!bdi_has_dirty_io(backing_dev_info))
 		return;
 
 	rcu_read_lock();
-	list_for_each_entry_rcu(wb, &q->backing_dev_info->wb_list, bdi_node)
+	list_for_each_entry_rcu(wb, &backing_dev_info->wb_list, bdi_node)
 		if (wb_has_dirty_io(wb))
 			wb_start_writeback(wb, nr_pages, true,
 					   WB_REASON_LAPTOP_TIMER);
-- 
2.7.4


-- 
Kees Cook
Pixel Security