@@ -149,15 +149,11 @@ void *class_handle2object(u64 cookie, char *owner)
if (h->h_cookie != cookie || h->h_owner != owner)
continue;
- spin_lock(&h->h_lock);
- if (likely(h->h_in != 0)) {
- refcount_inc(&h->h_ref);
- CDEBUG(D_INFO, "GET %s %p refcount=%d\n",
- h->h_owner, h,
- refcount_read(&h->h_ref));
- retval = h;
- }
- spin_unlock(&h->h_lock);
+ refcount_inc(&h->h_ref);
+ CDEBUG(D_INFO, "GET %s %p refcount=%d\n",
+ h->h_owner, h,
+ refcount_read(&h->h_ref));
+ retval = h;
break;
}
rcu_read_unlock();
There can be no value in this locking and test on h_in. If the lookup could have run in parallel with class_handle_unhash_nolock() and seen "h_in == 0", then it could equally well have run moments earlier and not seen it - no locking would prevent that, so the caller much be prepared to have an object returned which has already been unhashed by the time it sees the object. In other words, an interlock between unhash and lookup much be provided at a higher level than where this code is trying to handle it. So remove this pointless code. Signed-off-by: NeilBrown <neilb@suse.com> --- .../lustre/lustre/obdclass/lustre_handles.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-)