dlm: remove ls_local_handle from struct dlm_ls

This patch removes ls_local_handle from struct dlm_ls as it stores the
ls pointer of the top level structure itesef and this isn't necessary.
There is a lookup functionality to lookup the lockspace in
dlm_find_lockspace_local() but the given input parameter is the pointer
already. This might be more safe to lookup a lockspace but given a wrong
lockspace pointer is a bug in the code and we save the additional lookup
here. The dlm_ls structure can be still hidden by using dlm_lockspace_t
handle pointer.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

Author: Alexander Aring

fs/dlm/dlm_internal.h

@@ -561,7 +561,6 @@ struct rcom_lock {
 
 struct dlm_ls {
 	struct list_head	ls_list;	/* list of lockspaces */
-	dlm_lockspace_t		*ls_local_handle;
 	uint32_t		ls_global_id;	/* global unique lockspace ID */
 	uint32_t		ls_generation;
 	uint32_t		ls_exflags;

fs/dlm/lockspace.c

@@ -38,7 +38,7 @@ static ssize_t dlm_control_store(struct dlm_ls *ls, const char *buf, size_t len)
 
 	if (rc)
 		return rc;
-	ls = dlm_find_lockspace_local(ls->ls_local_handle);
+	ls = dlm_find_lockspace_local(ls);
 	if (!ls)
 		return -EINVAL;
 
@@ -265,18 +265,9 @@ struct dlm_ls *dlm_find_lockspace_global(uint32_t id)
 
 struct dlm_ls *dlm_find_lockspace_local(dlm_lockspace_t *lockspace)
 {
-	struct dlm_ls *ls;
+	struct dlm_ls *ls = lockspace;
 
-	spin_lock_bh(&lslist_lock);
-	list_for_each_entry(ls, &lslist, ls_list) {
-		if (ls->ls_local_handle == lockspace) {
-			atomic_inc(&ls->ls_count);
-			goto out;
-		}
-	}
-	ls = NULL;
- out:
-	spin_unlock_bh(&lslist_lock);
+	atomic_inc(&ls->ls_count);
 	return ls;
 }
 
@@ -496,7 +487,6 @@ static int new_lockspace(const char *name, const char *cluster,
 	idr_init(&ls->ls_recover_idr);
 	spin_lock_init(&ls->ls_recover_idr_lock);
 	ls->ls_recover_list_count = 0;
-	ls->ls_local_handle = ls;
 	init_waitqueue_head(&ls->ls_wait_general);
 	INIT_LIST_HEAD(&ls->ls_masters_list);
 	rwlock_init(&ls->ls_masters_lock);

fs/dlm/user.c

@@ -454,7 +454,7 @@ static int device_remove_lockspace(struct dlm_lspace_params *params)
 	if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 		force = 2;
 
-	lockspace = ls->ls_local_handle;
+	lockspace = ls;
 	dlm_put_lockspace(ls);
 
 	/* The final dlm_release_lockspace waits for references to go to
@@ -657,7 +657,7 @@ static int device_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 	}
 
-	proc->lockspace = ls->ls_local_handle;
+	proc->lockspace = ls;
 	INIT_LIST_HEAD(&proc->asts);
 	INIT_LIST_HEAD(&proc->locks);
 	INIT_LIST_HEAD(&proc->unlocking);