When we change the resource hash to rhashtable we won't have
a per-bucket counter.  We could use the nelems global counter,
but ldlm_resource goes to some trouble to avoid having any
table-wide atomics, and hopefully rhashtable will grow the
ability to disable the global counter in the near future.
Having a counter we control makes it easier to manage the
back-reference to the namespace when there is anything in the
hash table.

So add a counter to the ldlm_ns_bucket.

Signed-off-by: NeilBrown <ne...@suse.com>
---
 drivers/staging/lustre/lustre/include/lustre_dlm.h |    2 ++
 drivers/staging/lustre/lustre/ldlm/ldlm_resource.c |   10 +++++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre_dlm.h 
b/drivers/staging/lustre/lustre/include/lustre_dlm.h
index 395d50160dcc..ab90abe1c2d8 100644
--- a/drivers/staging/lustre/lustre/include/lustre_dlm.h
+++ b/drivers/staging/lustre/lustre/include/lustre_dlm.h
@@ -309,6 +309,8 @@ struct ldlm_ns_bucket {
         * fact the network or overall system load is at fault
         */
        struct adaptive_timeout     nsb_at_estimate;
+       /* counter of entries in this bucket */
+       atomic_t                nsb_count;
 };
 
 enum {
diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c 
b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
index 927544f01adc..669556420bdf 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
@@ -181,12 +181,11 @@ static ssize_t resource_count_show(struct kobject *kobj, 
struct attribute *attr,
        struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
                                                 ns_kobj);
        __u64             res = 0;
-       struct cfs_hash_bd        bd;
        int                 i;
 
        /* result is not strictly consistent */
-       cfs_hash_for_each_bucket(ns->ns_rs_hash, &bd, i)
-               res += cfs_hash_bd_count_get(&bd);
+       for (i = 0; i < (1 << ns->ns_bucket_bits); i++)
+               res += atomic_read(&ns->ns_rs_buckets[i].nsb_count);
        return sprintf(buf, "%lld\n", res);
 }
 LUSTRE_RO_ATTR(resource_count);
@@ -668,6 +667,7 @@ struct ldlm_namespace *ldlm_namespace_new(struct obd_device 
*obd, char *name,
                struct ldlm_ns_bucket *nsb = &ns->ns_rs_buckets[idx];
                at_init(&nsb->nsb_at_estimate, ldlm_enqueue_min, 0);
                nsb->nsb_namespace = ns;
+               atomic_set(&nsb->nsb_count, 0);
        }
 
        ns->ns_obd      = obd;
@@ -1144,7 +1144,7 @@ ldlm_resource_get(struct ldlm_namespace *ns, struct 
ldlm_resource *parent,
        }
        /* We won! Let's add the resource. */
        cfs_hash_bd_add_locked(ns->ns_rs_hash, &bd, &res->lr_hash);
-       if (cfs_hash_bd_count_get(&bd) == 1)
+       if (atomic_inc_return(&res->lr_ns_bucket->nsb_count) == 1)
                ns_refcount = ldlm_namespace_get_return(ns);
 
        cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1);
@@ -1202,7 +1202,7 @@ static void __ldlm_resource_putref_final(struct 
cfs_hash_bd *bd,
        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)
+       if (atomic_dec_and_test(&nsb->nsb_count))
                ldlm_namespace_put(ns);
        kmem_cache_free(ldlm_resource_slab, res);
 }


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