From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.7 required=3.0 tests=DATE_IN_PAST_96_XX, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BE8EC2D0E5 for ; Sat, 28 Mar 2020 16:43:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B2E52082D for ; Sat, 28 Mar 2020 16:43:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727742AbgC1Qnd (ORCPT ); Sat, 28 Mar 2020 12:43:33 -0400 Received: from mx.sdf.org ([205.166.94.20]:50199 "EHLO mx.sdf.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727461AbgC1QnV (ORCPT ); Sat, 28 Mar 2020 12:43:21 -0400 Received: from sdf.org (IDENT:lkml@sdf.lonestar.org [205.166.94.16]) by mx.sdf.org (8.15.2/8.14.5) with ESMTPS id 02SGhHan022954 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits) verified NO); Sat, 28 Mar 2020 16:43:17 GMT Received: (from lkml@localhost) by sdf.org (8.15.2/8.12.8/Submit) id 02SGhHN7015213; Sat, 28 Mar 2020 16:43:17 GMT Message-Id: <202003281643.02SGhHN7015213@sdf.org> From: George Spelvin Date: Fri, 29 Nov 2019 15:39:41 -0500 Subject: [RFC PATCH v1 27/50] drivers/s390/scsi/zcsp_fc.c: Use prandom_u32_max() for backoff To: linux-kernel@vger.kernel.org, lkml@sdf.org Cc: Heiko Carstens , Vasily Gorbik , Christian Borntraeger , linux-s390@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We don't need crypto-grade random numbers for randomized backoffs. (We could skip the if() if we wanted to rely on the undocumented fact that prandom_u32_max(0) always returns 0. That would be a net time saving it port_scan_backoff == 0 is rare; if it's common, the if() is false often enough to pay for itself. Not sure which applies here.) Signed-off-by: George Spelvin Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: linux-s390@vger.kernel.org --- drivers/s390/scsi/zfcp_fc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c index b018b61bd168e..d24cafe02708f 100644 --- a/drivers/s390/scsi/zfcp_fc.c +++ b/drivers/s390/scsi/zfcp_fc.c @@ -48,7 +48,7 @@ unsigned int zfcp_fc_port_scan_backoff(void) { if (!port_scan_backoff) return 0; - return get_random_int() % port_scan_backoff; + return prandom_u32_max(port_scan_backoff); } static void zfcp_fc_port_scan_time(struct zfcp_adapter *adapter) -- 2.26.0