From patchwork Mon Jan 24 18:43:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 536412 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 6CAACC433EF for ; Mon, 24 Jan 2022 18:55:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343788AbiAXSzf (ORCPT ); Mon, 24 Jan 2022 13:55:35 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:52854 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343868AbiAXSxm (ORCPT ); Mon, 24 Jan 2022 13:53:42 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2E5EA61509; Mon, 24 Jan 2022 18:53:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC0A3C340E8; Mon, 24 Jan 2022 18:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643050421; bh=Hy+ui+Jr/K4eBMHQYquo8g8R0kY5wd2sQfzD1NdsSPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SxI2SX0gZnQakCvxUjNMYqQR3VKczvV0nm95HJqHEe6xXVVMUFaONumKeaZMGviCL sbzf6M92l0zzkVCFZm/v6R22naHsud+u9bHc19dErcb77dsbiMmlFT95OWdOMuK9mw xrt1FWaCYWKXMfWwYYKNQcKlMqoRtNIGAsGBspEw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kevin Bracey , Eric Dumazet , Jiri Pirko , Vimalkumar , Jakub Kicinski Subject: [PATCH 4.4 112/114] net_sched: restore "mpu xxx" handling Date: Mon, 24 Jan 2022 19:43:27 +0100 Message-Id: <20220124183930.559884856@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183927.095545464@linuxfoundation.org> References: <20220124183927.095545464@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kevin Bracey commit fb80445c438c78b40b547d12b8d56596ce4ccfeb upstream. commit 56b765b79e9a ("htb: improved accuracy at high rates") broke "overhead X", "linklayer atm" and "mpu X" attributes. "overhead X" and "linklayer atm" have already been fixed. This restores the "mpu X" handling, as might be used by DOCSIS or Ethernet shaping: tc class add ... htb rate X overhead 4 mpu 64 The code being fixed is used by htb, tbf and act_police. Cake has its own mpu handling. qdisc_calculate_pkt_len still uses the size table containing values adjusted for mpu by user space. iproute2 tc has always passed mpu into the kernel via a tc_ratespec structure, but the kernel never directly acted on it, merely stored it so that it could be read back by `tc class show`. Rather, tc would generate length-to-time tables that included the mpu (and linklayer) in their construction, and the kernel used those tables. Since v3.7, the tables were no longer used. Along with "mpu", this also broke "overhead" and "linklayer" which were fixed in 01cb71d2d47b ("net_sched: restore "overhead xxx" handling", v3.10) and 8a8e3d84b171 ("net_sched: restore "linklayer atm" handling", v3.11). "overhead" was fixed by simply restoring use of tc_ratespec::overhead - this had originally been used by the kernel but was initially omitted from the new non-table-based calculations. "linklayer" had been handled in the table like "mpu", but the mode was not originally passed in tc_ratespec. The new implementation was made to handle it by getting new versions of tc to pass the mode in an extended tc_ratespec, and for older versions of tc the table contents were analysed at load time to deduce linklayer. As "mpu" has always been given to the kernel in tc_ratespec, accompanying the mpu-based table, we can restore system functionality with no userspace change by making the kernel act on the tc_ratespec value. Fixes: 56b765b79e9a ("htb: improved accuracy at high rates") Signed-off-by: Kevin Bracey Cc: Eric Dumazet Cc: Jiri Pirko Cc: Vimalkumar Link: https://lore.kernel.org/r/20220112170210.1014351-1-kevin@bracey.fi Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- include/net/sch_generic.h | 5 +++++ net/sched/sch_generic.c | 1 + 2 files changed, 6 insertions(+) --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -797,6 +797,7 @@ struct psched_ratecfg { u64 rate_bytes_ps; /* bytes per second */ u32 mult; u16 overhead; + u16 mpu; u8 linklayer; u8 shift; }; @@ -806,6 +807,9 @@ static inline u64 psched_l2t_ns(const st { len += r->overhead; + if (len < r->mpu) + len = r->mpu; + if (unlikely(r->linklayer == TC_LINKLAYER_ATM)) return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift; @@ -828,6 +832,7 @@ static inline void psched_ratecfg_getrat res->rate = min_t(u64, r->rate_bytes_ps, ~0U); res->overhead = r->overhead; + res->mpu = r->mpu; res->linklayer = (r->linklayer & TC_LINKLAYER_MASK); } --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -966,6 +966,7 @@ void psched_ratecfg_precompute(struct ps { memset(r, 0, sizeof(*r)); r->overhead = conf->overhead; + r->mpu = conf->mpu; r->rate_bytes_ps = max_t(u64, conf->rate, rate64); r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK); r->mult = 1;