staging/lustre/ldlm: engage ELC for all ldlm enqueue req

If there is no request passed into ldlm_cli_enqueue, the enqueue
request will not engage ELC to drop unneeded locks. currently,
this kind of request is mainly related to EXTENT locks enqueue
requests (except for glimpse EXTENT lock for it has an intent).
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: http://review.whamcloud.com/21739
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8209Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Vitaly Fertman <vitaly.fertman@seagate.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ldlm/ldlm_request.c

@@ -748,17 +748,14 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
 	lock->l_last_activity = ktime_get_real_seconds();
 
 	/* lock not sent to server yet */
-
 	if (!reqp || !*reqp) {
-		req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
-						&RQF_LDLM_ENQUEUE,
-						LUSTRE_DLM_VERSION,
-						LDLM_ENQUEUE);
-		if (!req) {
+		req = ldlm_enqueue_pack(exp, lvb_len);
+		if (IS_ERR(req)) {
 			failed_lock_cleanup(ns, lock, einfo->ei_mode);
 			LDLM_LOCK_RELEASE(lock);
-			return -ENOMEM;
+			return PTR_ERR(req);
 		}
+
 		req_passed_in = 0;
 		if (reqp)
 			*reqp = req;
@@ -778,16 +775,6 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
 	body->lock_flags = ldlm_flags_to_wire(*flags);
 	body->lock_handle[0] = *lockh;
 
-	/* Continue as normal. */
-	if (!req_passed_in) {
-		if (lvb_len > 0)
-			req_capsule_extend(&req->rq_pill,
-					   &RQF_LDLM_ENQUEUE_LVB);
-		req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
-				     lvb_len);
-		ptlrpc_request_set_replen(req);
-	}
-
 	/*
 	 * Liblustre client doesn't get extent locks, except for O_APPEND case
 	 * where [0, OBD_OBJECT_EOF] lock is taken, or truncate, where