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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 DACDAC282C3 for ; Tue, 22 Jan 2019 17:18:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B07C32085A for ; Tue, 22 Jan 2019 17:18:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729448AbfAVRSV (ORCPT ); Tue, 22 Jan 2019 12:18:21 -0500 Received: from mga11.intel.com ([192.55.52.93]:44147 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728719AbfAVRSV (ORCPT ); Tue, 22 Jan 2019 12:18:21 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Jan 2019 09:18:20 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,507,1539673200"; d="scan'208";a="140351942" Received: from tthayer-hp-z620.an.intel.com (HELO [10.122.105.146]) ([10.122.105.146]) by fmsmga001.fm.intel.com with ESMTP; 22 Jan 2019 09:18:20 -0800 Reply-To: thor.thayer@linux.intel.com Subject: Re: [PATCH] net: altera_tse: fix msgdma_tx_completion on non-zero fill_level case To: Atsushi Nemoto , netdev@vger.kernel.org Cc: Tomonori Sakita , Dalon Westergreen References: <20190121.172926.1822036089248860935.atsushi.nemoto@sord.co.jp> From: Thor Thayer Message-ID: Date: Tue, 22 Jan 2019 11:20:57 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190121.172926.1822036089248860935.atsushi.nemoto@sord.co.jp> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 1/21/19 2:29 AM, Atsushi Nemoto wrote: > From: Tomonori Sakita > > If fill_level was not zero and status was not BUSY, > result of "tx_prod - tx_cons - inuse" might be zero. > Subtracting 1 unconditionally results invalid negative return value > on this case. > The subtraction is not needed if fill_level was not zero. > > Signed-off-by: Tomonori Sakita > Signed-off-by: Atsushi Nemoto > --- > drivers/net/ethernet/altera/altera_msgdma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/altera/altera_msgdma.c b/drivers/net/ethernet/altera/altera_msgdma.c > index 0fb986b..3df73d3 100644 > --- a/drivers/net/ethernet/altera/altera_msgdma.c > +++ b/drivers/net/ethernet/altera/altera_msgdma.c > @@ -145,7 +145,7 @@ u32 msgdma_tx_completions(struct altera_tse_private *priv) > & 0xffff; > > if (inuse) { /* Tx FIFO is not empty */ > - ready = priv->tx_prod - priv->tx_cons - inuse - 1; > + ready = priv->tx_prod - priv->tx_cons - inuse; > } else { > /* Check for buffered last packet */ > status = csrrd32(priv->tx_dma_csr, msgdma_csroffs(status)); > I'm adding Dalon who has done a lot of work on msgdma. I'd like to get his comments. Thanks, Thor