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 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 A6D93C282C3 for ; Fri, 25 Jan 2019 02:03:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74A58218D2 for ; Fri, 25 Jan 2019 02:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728365AbfAYCDO (ORCPT ); Thu, 24 Jan 2019 21:03:14 -0500 Received: from ms2.toshiba-tops.co.jp ([61.200.21.4]:49895 "EHLO dmz-ms2.toshiba-tops.co.jp" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727983AbfAYCDO (ORCPT ); Thu, 24 Jan 2019 21:03:14 -0500 Received: from [192.168.254.254] ([192.168.254.254]) by dmz-ms2.toshiba-tops.co.jp ([192.168.254.3]) with ESMTP id 1548381748.356648.51821472.dmz-ms2 for <>; Fri, 25 Jan 2019 11:02:28 +0900 (JST) Received: from localhost (172.17.28.65) by TPSSRV64.toshiba-tops.co.jp (172.16.4.164) with Microsoft SMTP Server id 14.2.318.1; Fri, 25 Jan 2019 11:02:23 +0900 Date: Fri, 25 Jan 2019 11:02:22 +0900 Message-ID: <20190125.110222.956948485194493083.atsushi.nemoto@sord.co.jp> To: Thor Thayer , CC: Dalon L Westergreen , Tomonori Sakita Subject: [PATCH v2] net: altera_tse: fix msgdma_tx_completion on non-zero fill_level case X-TERRACE-DUMMYSUBJECT: Terrace Spam system * From: Atsushi Nemoto X-Fingerprint: 6ACA 1623 39BD 9A94 9B1A B746 CA77 FE94 2874 D52F X-Pgp-Public-Key: http://wwwkeys.pgp.net:11371/pks/lookup?op=get&search=0x2874D52F X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-TERRACE-SPAMMARK: NO (SR:19.80) (by Terrace) X-TERRACE-SID: 1548381748.356648.51821472.dmz-ms2 X-TERRACE-CLASSID: Terrace Spam system Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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. Make sure not to return an negative value. Signed-off-by: Tomonori Sakita Signed-off-by: Atsushi Nemoto Reviewed-by: Dalon L Westergreen --- Changes in v2: Use max_t instead of just removing the "- 1". drivers/net/ethernet/altera/altera_msgdma.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/altera/altera_msgdma.c b/drivers/net/ethernet/altera/altera_msgdma.c index 0fb986b..0ae723f 100644 --- a/drivers/net/ethernet/altera/altera_msgdma.c +++ b/drivers/net/ethernet/altera/altera_msgdma.c @@ -145,7 +145,8 @@ 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 = max_t(int, + priv->tx_prod - priv->tx_cons - inuse - 1, 0); } else { /* Check for buffered last packet */ status = csrrd32(priv->tx_dma_csr, msgdma_csroffs(status)); -- 2.1.4