staging: lustre: use explicit poll loop in ptlrpc_service_unlink_rqbd

Rather an using l_wait_event(), use wait_event_idle_timeout()
with an explicit loop so it is easier to see what is happening.
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Patrick Farrell <paf@cray.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ptlrpc/service.c

@@ -2618,7 +2618,7 @@ ptlrpc_service_unlink_rqbd(struct ptlrpc_service *svc)
 {
 	struct ptlrpc_service_part *svcpt;
 	struct ptlrpc_request_buffer_desc *rqbd;
-	struct l_wait_info lwi;
+	int cnt;
 	int rc;
 	int i;
 
@@ -2658,12 +2658,13 @@ ptlrpc_service_unlink_rqbd(struct ptlrpc_service *svc)
 			 * the HUGE timeout lets us CWARN for visibility
 			 * of sluggish LNDs
 			 */
-			lwi = LWI_TIMEOUT_INTERVAL(
-					LONG_UNLINK * HZ,
-					HZ, NULL, NULL);
-			rc = l_wait_event(svcpt->scp_waitq,
-					  svcpt->scp_nrqbds_posted == 0, &lwi);
-			if (rc == -ETIMEDOUT) {
+			cnt = 0;
+			while (cnt < LONG_UNLINK &&
+			       (rc = wait_event_idle_timeout(svcpt->scp_waitq,
+							     svcpt->scp_nrqbds_posted == 0,
+							     HZ)) == 0)
+				cnt ++;
+			if (rc == 0) {
 				CWARN("Service %s waiting for request buffers\n",
 				      svcpt->scp_service->srv_name);
 			}