btrfs: scrub: remove btrfs_fs_info::scrub_wr_completion_workers

Since the scrub rework introduced by commit 2af2aaf98205 ("btrfs:
scrub: introduce structure for new BTRFS_STRIPE_LEN based interface")
and later commits, scrub only needs one single workqueue,
fs_info::scrub_worker.

That scrub_wr_completion_workers is initially to handle the delay work
after write bios finished.  But the new scrub code goes submit-and-wait
for write bios, thus all the work are done inside the scrub_worker.

The last user of fs_info::scrub_wr_completion_workers is removed in
commit 16f93993498b ("btrfs: scrub: remove the old writeback
infrastructure"), so we can safely remove the workqueue.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
index 5dd24c2916a1..396e2a463480 100644
--- a/fs/btrfs/fs.h
+++ b/fs/btrfs/fs.h
@@ -642,7 +642,6 @@ struct btrfs_fs_info {
 	 */
 	refcount_t scrub_workers_refcnt;
 	struct workqueue_struct *scrub_workers;
-	struct workqueue_struct *scrub_wr_completion_workers;
 	struct btrfs_subpage_info *subpage_info;
 
 	struct btrfs_discard_ctl discard_ctl;