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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 541FAC3DA78 for ; Sun, 15 Jan 2023 11:26:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230517AbjAOLZ6 (ORCPT ); Sun, 15 Jan 2023 06:25:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230478AbjAOLZ5 (ORCPT ); Sun, 15 Jan 2023 06:25:57 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCF583A87 for ; Sun, 15 Jan 2023 03:25:55 -0800 (PST) From: Kurt Kanzenbach DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1673781953; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3v1EntWB9hscrgaIPvzEN6voYTcu4tzD4oH9Pvcik70=; b=QHRrcOjqaU6gOJh2GwD90044Xulnze2UDWAkOMsW3H/MO3a92UW9nReWRSw+2ey8EUNlgB IBhE++6d2RQboeH/kF4gYs/ssupV88BpNe3GpR736q+kWR3CeWoafpCHGs8hRS4HY4SZlc x4IbX+2THVRYi80fV5fgeiO/7NLJuQuTHPkfOC4dNPHZZYSRoaxvnNyKgYINmAtX+pj3VH Dx1RdL1wYo8ySiKcknr3COj3NtONoTTXAvalrsIIj8Sv+7nUkHIxiwxPokH1nm0/n4sQzw 3EWSWON3esQA5AU0ibRmT2JIKYEts3YGBOys+V79/rTZzPVwOK80+YvMxrrq+g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1673781953; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3v1EntWB9hscrgaIPvzEN6voYTcu4tzD4oH9Pvcik70=; b=8/oL2NIMXFE5EeJfeMRnIpVFTA2L9ufWBACyy2kbNZg34BL/x6FwMj7JVnhEgxRy21eRJT LvMU3nkKzZUi9mDg== To: Andrew Lunn Cc: Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, Vijayakannan Ayyathurai , Wong Vee Khee Subject: Re: [PATCH net v1] net: stmmac: Fix queue statistics reading In-Reply-To: References: <20230114120437.383514-1-kurt@linutronix.de> Date: Sun, 15 Jan 2023 12:25:51 +0100 Message-ID: <87fsccvy2o.fsf@kurt> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org --=-=-= Content-Type: text/plain Hi Andrew, On Sat Jan 14 2023, Andrew Lunn wrote: > On Sat, Jan 14, 2023 at 01:04:37PM +0100, Kurt Kanzenbach wrote: >> Correct queue statistics reading. All queue statistics are stored as unsigned >> long values. The retrieval for ethtool fetches these values as u64. However, on >> some systems the size of the counters are 32 bit. > >> @@ -551,16 +551,16 @@ static void stmmac_get_per_qstats(struct stmmac_priv *priv, u64 *data) >> p = (char *)priv + offsetof(struct stmmac_priv, >> xstats.txq_stats[q].tx_pkt_n); >> for (stat = 0; stat < STMMAC_TXQ_STATS; stat++) { >> - *data++ = (*(u64 *)p); >> - p += sizeof(u64 *); >> + *data++ = (*(unsigned long *)p); >> + p += sizeof(unsigned long); > > As you said in the comment, the register is 32 bits. Maybe the commit message is a bit misleading. There are no registers involved here. The queue statistics are accounted in software. See stmmac_txq_stats and stmmac_rxq_stats. > So maybe u32 would be better than unsigned long? The problem is pkt_n and irq_n are stored as longs. The size of these are either 4 or 8 byte depending on the architecture this code runs on. I my opinion we cannot use u32 or u64 for that reason. BTW, all the other stmmac statistic counters follow a different pattern. For example: for (i = 0; i < STMMAC_MMC_STATS_LEN; i++) { char *p; p = (char *)priv + stmmac_mmc[i].stat_offset; data[j++] = (stmmac_mmc[i].sizeof_stat == sizeof(u64)) ? (*(u64 *)p) : (*(u32 *)p); } > And it would also avoid issues if this code is every used on a 64 bit > machine. The current code runs fine on 64 bit architectures such as Intel EHL, TGL, ADL, ... I'm trying to fix it for the 32 bit case. Thanks, Kurt --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJHBAEBCgAxFiEEvLm/ssjDfdPf21mSwZPR8qpGc4IFAmPD4r8THGt1cnRAbGlu dXRyb25peC5kZQAKCRDBk9HyqkZzgmc8D/4h+vMhAUUx7drZC4OK6MBVCFufO0og sqc+WGKXshmvywbY83xQC6fsdm4pQDSJ0CjjX5x3Xfqr4S9V7jvkd3jG350nS5vt 1SHMvBQAcRbABV23e35cr+nTHRaN+zL/wTMWk+ZaA4zhwWztE46WwwsmPw//EI8S jfWqKDfYpi4UIMlaZhm5AQtCBRGnfb/7+wzOUOELi1GIFbzq4HJ6jcq9diJamo5Q N26HSk/fRHM3NtuCtHWe4nyjRguHEEOXGJqOakgdtUIcXAz/AQ4IgH+BekyUyKW3 TywTcRVUz3rxV21ttPTIGd3lKEN5MRrHTXBnds0RieVyJMwWMkppcZuckbYuZrXv HKiASH76ap5AvKy6VKkjU5LTSoX/yH7l6sx47vPiUhtJ2/V83S5t24i53av3J5QX F8K+FzvL+4kbZKcMJhTprmDO+5ojgaoXtzsC1nQjPZmv7W4EB50iMDhASUMrheiU PN3OSApBIGzn8A5qJ/noy7GN5/4zDDsUBdhd4zi4zQfLYSpEC6lUo/Xhy8BtjY85 hDRcI3cpmVBEyc3c6gfK2REms++mDJ+TH2BsmMJaeQinFY1RzWNgyUD9uYIhkOqe Ou/Oev4snyalP3EVwXWdQcjXkBUdM9ZLMtD+bagR2pZTov8g9YBClk/zoMjGb8RF HnomIheLXGeuAg== =eYvN -----END PGP SIGNATURE----- --=-=-=--