cifs: use workqueue instead of slow-work

Workqueue can now handle high concurrency.  Use system_nrt_wq
instead of slow-work.

* Updated is_valid_oplock_break() to not call cifs_oplock_break_put()
  as advised by Steve French.  It might cause deadlock.  Instead,
  reference is increased after queueing succeeded and
  cifs_oplock_break() briefly grabs GlobalSMBSeslock before putting
  the cfile to make sure it doesn't put before the matching get is
  finished.

* Anton Blanchard reported that cifs conversion was using now gone
  system_single_wq.  Use system_nrt_wq which provides non-reentrance
  guarantee which is enough and much better.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Steve French <sfrench@samba.org>
Cc: Anton Blanchard <anton@samba.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 391816b461ca..b066e73c4153 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -162,7 +162,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle,
         mutex_init(&pCifsFile->lock_mutex);
         INIT_LIST_HEAD(&pCifsFile->llist);
         atomic_set(&pCifsFile->count, 1);
-        slow_work_init(&pCifsFile->oplock_break, &cifs_oplock_break_ops);
+        INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
 
         write_lock(&GlobalSMBSeslock);
         list_add(&pCifsFile->tlist, &cifs_sb->tcon->openFileList);