btrfs: Replace fs_info->rmw_workers workqueue with btrfs_workqueue.

Replace the fs_info->rmw_workers with the newly created
btrfs_workqueue.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>

fs/btrfs/ctree.h

@@ -1511,7 +1511,7 @@ struct btrfs_fs_info {
 	struct btrfs_workqueue_struct *endio_workers;
 	struct btrfs_workqueue_struct *endio_meta_workers;
 	struct btrfs_workqueue_struct *endio_raid56_workers;
-	struct btrfs_workers rmw_workers;
+	struct btrfs_workqueue_struct *rmw_workers;
 	struct btrfs_workqueue_struct *endio_meta_write_workers;
 	struct btrfs_workqueue_struct *endio_write_workers;
 	struct btrfs_workqueue_struct *endio_freespace_worker;

fs/btrfs/disk-io.c

@@ -2001,7 +2001,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->endio_workers);
 	btrfs_destroy_workqueue(fs_info->endio_meta_workers);
 	btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
-	btrfs_stop_workers(&fs_info->rmw_workers);
+	btrfs_destroy_workqueue(fs_info->rmw_workers);
 	btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
 	btrfs_destroy_workqueue(fs_info->endio_write_workers);
 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
@@ -2513,9 +2513,8 @@ int open_ctree(struct super_block *sb,
 		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
 	fs_info->endio_raid56_workers =
 		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
-	btrfs_init_workers(&fs_info->rmw_workers,
-			   "rmw", fs_info->thread_pool_size,
-			   &fs_info->generic_worker);
+	fs_info->rmw_workers =
+		btrfs_alloc_workqueue("rmw", flags, max_active, 2);
 	fs_info->endio_write_workers =
 		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
 	fs_info->endio_freespace_worker =
@@ -2529,8 +2528,6 @@ int open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
 			   &fs_info->generic_worker);
 
-	fs_info->rmw_workers.idle_thresh = 2;
-
 	fs_info->readahead_workers.idle_thresh = 2;
 
 	/*
@@ -2539,7 +2536,6 @@ int open_ctree(struct super_block *sb,
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
 	ret |= btrfs_start_workers(&fs_info->fixup_workers);
-	ret |= btrfs_start_workers(&fs_info->rmw_workers);
 	ret |= btrfs_start_workers(&fs_info->delayed_workers);
 	ret |= btrfs_start_workers(&fs_info->caching_workers);
 	ret |= btrfs_start_workers(&fs_info->readahead_workers);
@@ -2553,7 +2549,7 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
 	      fs_info->endio_meta_write_workers &&
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
-	      fs_info->endio_freespace_worker)) {
+	      fs_info->endio_freespace_worker && fs_info->rmw_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}

fs/btrfs/raid56.c

@@ -87,7 +87,7 @@ struct btrfs_raid_bio {
 	/*
 	 * for scheduling work in the helper threads
 	 */
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 
 	/*
 	 * bio list and bio_list_lock are used
@@ -166,8 +166,8 @@ struct btrfs_raid_bio {
 
 static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
 static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
-static void rmw_work(struct btrfs_work *work);
-static void read_rebuild_work(struct btrfs_work *work);
+static void rmw_work(struct btrfs_work_struct *work);
+static void read_rebuild_work(struct btrfs_work_struct *work);
 static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
 static void async_read_rebuild(struct btrfs_raid_bio *rbio);
 static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
@@ -1416,20 +1416,18 @@ static void raid_rmw_end_io(struct bio *bio, int err)
 
 static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
 {
-	rbio->work.flags = 0;
-	rbio->work.func = rmw_work;
+	btrfs_init_work(&rbio->work, rmw_work, NULL, NULL);
 
-	btrfs_queue_worker(&rbio->fs_info->rmw_workers,
-			   &rbio->work);
+	btrfs_queue_work(rbio->fs_info->rmw_workers,
+			 &rbio->work);
 }
 
 static void async_read_rebuild(struct btrfs_raid_bio *rbio)
 {
-	rbio->work.flags = 0;
-	rbio->work.func = read_rebuild_work;
+	btrfs_init_work(&rbio->work, read_rebuild_work, NULL, NULL);
 
-	btrfs_queue_worker(&rbio->fs_info->rmw_workers,
-			   &rbio->work);
+	btrfs_queue_work(rbio->fs_info->rmw_workers,
+			 &rbio->work);
 }
 
 /*
@@ -1590,7 +1588,7 @@ struct btrfs_plug_cb {
 	struct blk_plug_cb cb;
 	struct btrfs_fs_info *info;
 	struct list_head rbio_list;
-	struct btrfs_work work;
+	struct btrfs_work_struct work;
 };
 
 /*
@@ -1654,7 +1652,7 @@ static void run_plug(struct btrfs_plug_cb *plug)
  * if the unplug comes from schedule, we have to push the
  * work off to a helper thread
  */
-static void unplug_work(struct btrfs_work *work)
+static void unplug_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_plug_cb *plug;
 	plug = container_of(work, struct btrfs_plug_cb, work);
@@ -1667,10 +1665,9 @@ static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
 	plug = container_of(cb, struct btrfs_plug_cb, cb);
 
 	if (from_schedule) {
-		plug->work.flags = 0;
-		plug->work.func = unplug_work;
-		btrfs_queue_worker(&plug->info->rmw_workers,
-				   &plug->work);
+		btrfs_init_work(&plug->work, unplug_work, NULL, NULL);
+		btrfs_queue_work(plug->info->rmw_workers,
+				 &plug->work);
 		return;
 	}
 	run_plug(plug);
@@ -2082,7 +2079,7 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
 
 }
 
-static void rmw_work(struct btrfs_work *work)
+static void rmw_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_raid_bio *rbio;
 
@@ -2090,7 +2087,7 @@ static void rmw_work(struct btrfs_work *work)
 	raid56_rmw_stripe(rbio);
 }
 
-static void read_rebuild_work(struct btrfs_work *work)
+static void read_rebuild_work(struct btrfs_work_struct *work)
 {
 	struct btrfs_raid_bio *rbio;