[PATCH 06/17] staging: lustre: tidy up ldlm_resource_putref()

[NeilBrown]

1/ the return value of ldlm_resource_putref() is never
  used, so change it to return 'void'.
2/ Move all of the code to run on the last putref to
   __ldlm_resource_putref_final().  This means a lock
   is taken in one function and dropped in another, but
   that isn't too uncommon, and will disappear in a future
   patch.
   Now that the code it together, it becomes apparent that
   we are dropping a ref on the namespace *before* the last
   use.  So keep the ref until after.

Signed-off-by: NeilBrown <ne...@suse.com>
---
 drivers/staging/lustre/lustre/include/lustre_dlm.h |    2 +-
 drivers/staging/lustre/lustre/ldlm/ldlm_resource.c |   21 +++++++++-----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre_dlm.h 
b/drivers/staging/lustre/lustre/include/lustre_dlm.h
index 5a355fbab401..d668d86423a4 100644
--- a/drivers/staging/lustre/lustre/include/lustre_dlm.h
+++ b/drivers/staging/lustre/lustre/include/lustre_dlm.h
@@ -1190,7 +1190,7 @@ struct ldlm_resource *ldlm_resource_get(struct 
ldlm_namespace *ns,
                                        struct ldlm_resource *parent,
                                        const struct ldlm_res_id *,
                                        enum ldlm_type type, int create);
-int ldlm_resource_putref(struct ldlm_resource *res);
+void ldlm_resource_putref(struct ldlm_resource *res);
 void ldlm_resource_add_lock(struct ldlm_resource *res,
                            struct list_head *head,
                            struct ldlm_lock *lock);
diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c 
b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
index 4c44603ab6f9..8841a1bb2c0a 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
@@ -1195,6 +1195,7 @@ static void __ldlm_resource_putref_final(struct 
cfs_hash_bd *bd,
                                         struct ldlm_resource *res)
 {
        struct ldlm_ns_bucket *nsb = res->lr_ns_bucket;
+       struct ldlm_namespace *ns = nsb->nsb_namespace;
 
        if (!list_empty(&res->lr_granted)) {
                ldlm_resource_dump(D_ERROR, res);
@@ -1206,15 +1207,18 @@ static void __ldlm_resource_putref_final(struct 
cfs_hash_bd *bd,
                LBUG();
        }
 
-       cfs_hash_bd_del_locked(nsb->nsb_namespace->ns_rs_hash,
+       cfs_hash_bd_del_locked(ns->ns_rs_hash,
                               bd, &res->lr_hash);
        lu_ref_fini(&res->lr_reference);
+       cfs_hash_bd_unlock(ns->ns_rs_hash, bd, 1);
+       if (ns->ns_lvbo && ns->ns_lvbo->lvbo_free)
+               ns->ns_lvbo->lvbo_free(res);
        if (cfs_hash_bd_count_get(bd) == 0)
-               ldlm_namespace_put(nsb->nsb_namespace);
+               ldlm_namespace_put(ns);
+       kmem_cache_free(ldlm_resource_slab, res);
 }
 
-/* Returns 1 if the resource was freed, 0 if it remains. */
-int ldlm_resource_putref(struct ldlm_resource *res)
+void ldlm_resource_putref(struct ldlm_resource *res)
 {
        struct ldlm_namespace *ns = ldlm_res_to_ns(res);
        struct cfs_hash_bd   bd;
@@ -1224,15 +1228,8 @@ int ldlm_resource_putref(struct ldlm_resource *res)
               res, atomic_read(&res->lr_refcount) - 1);
 
        cfs_hash_bd_get(ns->ns_rs_hash, &res->lr_name, &bd);
-       if (cfs_hash_bd_dec_and_lock(ns->ns_rs_hash, &bd, &res->lr_refcount)) {
+       if (cfs_hash_bd_dec_and_lock(ns->ns_rs_hash, &bd, &res->lr_refcount))
                __ldlm_resource_putref_final(&bd, res);
-               cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1);
-               if (ns->ns_lvbo && ns->ns_lvbo->lvbo_free)
-                       ns->ns_lvbo->lvbo_free(res);
-               kmem_cache_free(ldlm_resource_slab, res);
-               return 1;
-       }
-       return 0;
 }
 EXPORT_SYMBOL(ldlm_resource_putref);