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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 B055BC28CC7 for ; Mon, 10 Jun 2019 14:02:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FC7320679 for ; Mon, 10 Jun 2019 14:02:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390669AbfFJOCt (ORCPT ); Mon, 10 Jun 2019 10:02:49 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:18542 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390384AbfFJOCs (ORCPT ); Mon, 10 Jun 2019 10:02:48 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 0C55D96CA51B27A67399; Mon, 10 Jun 2019 22:02:43 +0800 (CST) Received: from [127.0.0.1] (10.177.96.96) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.439.0; Mon, 10 Jun 2019 22:02:42 +0800 Subject: Re: [PATCH -next] packet: remove unused variable 'status' in __packet_lookup_frame_in_block To: Willem de Bruijn References: <20190610115831.175710-1-maowenan@huawei.com> CC: David Miller , Network Development , LKML , From: maowenan Message-ID: Date: Mon, 10 Jun 2019 22:02:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.96.96] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/6/10 21:05, Willem de Bruijn wrote: > On Mon, Jun 10, 2019 at 8:17 AM Mao Wenan wrote: >> >> The variable 'status' in __packet_lookup_frame_in_block() is never used since >> introduction in commit f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer >> implementation."), we can remove it. >> And when __packet_lookup_frame_in_block() calls prb_retire_current_block(), >> it can pass macro TP_STATUS_KERNEL instead of 0. >> >> Signed-off-by: Mao Wenan >> --- >> net/packet/af_packet.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c >> index a29d66d..fb1a79c 100644 >> --- a/net/packet/af_packet.c >> +++ b/net/packet/af_packet.c >> @@ -1003,7 +1003,6 @@ static void prb_fill_curr_block(char *curr, >> /* Assumes caller has the sk->rx_queue.lock */ >> static void *__packet_lookup_frame_in_block(struct packet_sock *po, >> struct sk_buff *skb, >> - int status, >> unsigned int len >> ) >> { >> @@ -1046,7 +1045,7 @@ static void *__packet_lookup_frame_in_block(struct packet_sock *po, >> } >> >> /* Ok, close the current block */ >> - prb_retire_current_block(pkc, po, 0); >> + prb_retire_current_block(pkc, po, TP_STATUS_KERNEL); > > I don't think that 0 is intended to mean TP_STATUS_KERNEL here. > > prb_retire_current_block calls prb_close_block which sets status to > > TP_STATUS_USER | stat > > where stat is 0 or TP_STATUS_BLK_TMO. #define TP_STATUS_KERNEL 0 #define TP_STATUS_BLK_TMO (1 << 5) Actually, packet_current_rx_frame calls __packet_lookup_frame_in_block with status=TP_STATUS_KERNEL in original code. __packet_lookup_frame_in_block in this function, first is to check whether the currently active block has enough space for the packet, which means status of block should be TP_STATUS_KERNEL, then it calls prb_retire_current_block to retire this block. Since there needs some discussion about means of status, I can send v2 only removing the parameter status of __packet_lookup_frame_in_block? > >