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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 B1423C169C4 for ; Mon, 11 Feb 2019 09:47:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 863FD2082F for ; Mon, 11 Feb 2019 09:47:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726173AbfBKJrP (ORCPT ); Mon, 11 Feb 2019 04:47:15 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:51871 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725931AbfBKJrP (ORCPT ); Mon, 11 Feb 2019 04:47:15 -0500 Received: by mail-wm1-f65.google.com with SMTP id b11so16411214wmj.1 for ; Mon, 11 Feb 2019 01:47:13 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=NjQffYfwqXAAXDWvUUZYm7OxJR3TKi0I1dmjUrCSfig=; b=sDzmTCrFoyQqAvXmsWTDfaGmWPKFIetEr2FgsHtFiElPCvFdKGhMLUjw7LCxtYK018 +t/HzEpn9WX4kn8lbO38XEKdsn1n2nSEj7BgbRIQnfYO1OftlZqaT73bd5EE4aPZJESQ pGzcHS0O8Wbp8s+lJ9GKCMz6Dr53ekRdJL04UoHpEA0OJSNOnP8Eu0QLHzI/tT0YU836 7TgAe7pkVRF0v9BuD5tL8c4KiQ8UfAZlZR0FtrNdyZVjEsTNjrg3sNTrppxPVCG7MCW7 S0fVnOlfX+wMisWxtIzPy0vykjPt0ZbFMc4b3gpYJwlfi5nK0RIrYmxpsc+EtC28Qiv8 NTwg== X-Gm-Message-State: AHQUAuYlix+BNCy5g06mm8zZciHLrZH62/vlWwC4pWB1Ond6Oi40GuEz woEY6Hda3gIj955D/7pE0dDlhw== X-Google-Smtp-Source: AHgI3IaEQfspyF7J4BKmTbt/IF29JqYoxmdIAX7vNdZxF5zJC31FUhDBcGoqy3NH9L8ZGOkTooalYg== X-Received: by 2002:adf:b68a:: with SMTP id j10mr13432959wre.224.1549878432983; Mon, 11 Feb 2019 01:47:12 -0800 (PST) Received: from localhost.localdomain (nat-pool-mxp-t.redhat.com. [149.6.153.186]) by smtp.gmail.com with ESMTPSA id l6sm7054881wrv.70.2019.02.11.01.47.11 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Feb 2019 01:47:12 -0800 (PST) Date: Mon, 11 Feb 2019 10:47:10 +0100 From: Lorenzo Bianconi To: Stanislaw Gruszka Cc: Felix Fietkau , linux-wireless@vger.kernel.org Subject: Re: [RFC] mt76x02u: correct pad for fragments Message-ID: <20190211094708.GA3467@localhost.localdomain> References: <1549874264-7661-1-git-send-email-sgruszka@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1549874264-7661-1-git-send-email-sgruszka@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org > Modifying skb->len & data_len doesn't look correct. Issue is not critical > we just pad 2 times, except first padding is not filled with zeros. > > However I'm not sure if we should not add pad to all skb's in frags > list. Hi Stanislaw, IIRC the first packet of a A-MSDU burst keeps track of the burst length so if we add the a pad to last one we need to update the skb->len/data_len of the first one. No need to pad all skbs in the frag list, just last one Regards, Lorenzo > Additionally remove unlikely(pad) condition, we always pad for at least > four bytes what is needed by HW. > > Signed-off-by: Stanislaw Gruszka > --- > .../wireless/mediatek/mt76/mt76x02_usb_core.c | 22 +++++++------------ > 1 file changed, 8 insertions(+), 14 deletions(-) > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c > index dc2226c722dd..c7ca2d93720a 100644 > --- a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c > +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c > @@ -49,21 +49,15 @@ int mt76x02u_skb_dma_info(struct sk_buff *skb, int port, u32 flags) > FIELD_PREP(MT_TXD_INFO_DPORT, port) | flags; > put_unaligned_le32(info, skb_push(skb, sizeof(info))); > > - pad = round_up(skb->len, 4) + 4 - skb->len; > - skb_walk_frags(skb, iter) { > + skb_walk_frags(skb, iter) > last = iter; > - if (!iter->next) { > - skb->data_len += pad; > - skb->len += pad; > - break; > - } > - } > - > - if (unlikely(pad)) { > - if (skb_pad(last, pad)) > - return -ENOMEM; > - __skb_put(last, pad); > - } > + > + /* Add zero pad of 4 - 7 bytes at the end of buffer */ > + pad = round_up(skb->len, 4) + 4 - skb->len; > + if (skb_pad(last, pad)) > + return -ENOMEM; > + __skb_put(last, pad); > + > return 0; > } > > -- > 2.19.2 >