fs: dlm: change ls_clear_proc_locks to spinlock

This patch changes the ls_clear_proc_locks to a spinlock because there
is no need to handle it as a mutex as there is no sleepable context when
ls_clear_proc_locks is held. This allows us to call those functionality
in non-sleepable contexts.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/dlm_internal.h

@@ -661,7 +661,7 @@ struct dlm_ls {
 	spinlock_t		ls_recover_idr_lock;
 	wait_queue_head_t	ls_wait_general;
 	wait_queue_head_t	ls_recover_lock_wait;
-	struct mutex		ls_clear_proc_locks;
+	spinlock_t		ls_clear_proc_locks;
 
 	struct list_head	ls_root_list;	/* root resources */
 	struct rw_semaphore	ls_root_sem;	/* protect root_list */

fs/dlm/lock.c

@@ -6215,7 +6215,7 @@ static struct dlm_lkb *del_proc_lock(struct dlm_ls *ls,
 {
 	struct dlm_lkb *lkb = NULL;
 
-	mutex_lock(&ls->ls_clear_proc_locks);
+	spin_lock(&ls->ls_clear_proc_locks);
 	if (list_empty(&proc->locks))
 		goto out;
 
@@ -6227,7 +6227,7 @@ static struct dlm_lkb *del_proc_lock(struct dlm_ls *ls,
 	else
 		lkb->lkb_flags |= DLM_IFL_DEAD;
  out:
-	mutex_unlock(&ls->ls_clear_proc_locks);
+	spin_unlock(&ls->ls_clear_proc_locks);
 	return lkb;
 }
 
@@ -6264,7 +6264,7 @@ void dlm_clear_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc)
 		dlm_put_lkb(lkb);
 	}
 
-	mutex_lock(&ls->ls_clear_proc_locks);
+	spin_lock(&ls->ls_clear_proc_locks);
 
 	/* in-progress unlocks */
 	list_for_each_entry_safe(lkb, safe, &proc->unlocking, lkb_ownqueue) {
@@ -6280,7 +6280,7 @@ void dlm_clear_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc)
 		dlm_put_lkb(lkb);
 	}
 
-	mutex_unlock(&ls->ls_clear_proc_locks);
+	spin_unlock(&ls->ls_clear_proc_locks);
 	dlm_unlock_recovery(ls);
 }
 

fs/dlm/lockspace.c

@@ -584,7 +584,7 @@ static int new_lockspace(const char *name, const char *cluster,
 	atomic_set(&ls->ls_requestqueue_cnt, 0);
 	init_waitqueue_head(&ls->ls_requestqueue_wait);
 	mutex_init(&ls->ls_requestqueue_mutex);
-	mutex_init(&ls->ls_clear_proc_locks);
+	spin_lock_init(&ls->ls_clear_proc_locks);
 
 	/* Due backwards compatibility with 3.1 we need to use maximum
 	 * possible dlm message size to be sure the message will fit and

fs/dlm/user.c

@@ -184,7 +184,7 @@ void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
 		return;
 
 	ls = lkb->lkb_resource->res_ls;
-	mutex_lock(&ls->ls_clear_proc_locks);
+	spin_lock(&ls->ls_clear_proc_locks);
 
 	/* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
 	   can't be delivered.  For ORPHAN's, dlm_clear_proc_locks() freed
@@ -230,7 +230,7 @@ void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
 		spin_unlock(&proc->locks_spin);
 	}
  out:
-	mutex_unlock(&ls->ls_clear_proc_locks);
+	spin_unlock(&ls->ls_clear_proc_locks);
 }
 
 static int device_user_lock(struct dlm_user_proc *proc,