From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39BEF41B8C7 for ; Wed, 5 Aug 2026 10:01:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785924118; cv=none; b=KXElJKW2ondzHGpKzsfkXLnrE7k6Tq1vow/3c5vqdf0b9+58RwJxNcEjLRTC8CkqCz2S2Ohks65P4Drg7KnnN76SbqqcDNVADWXXbwNUj4ih7u7StNFpe5KefDx8CwV/mpJb5tpy5CMIHQoI1+Lc/6H7glrnqehvBnFEtYR4u54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785924118; c=relaxed/simple; bh=804MoK1/qgKtYK1haJrkmGhKwa9+WxJwxY1NN0N6G1A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X0gH76850zy2YjEsrN6QC88+kHGi3bx8cwkrEy9ngTn3RxuD32goRdrc46OKuTlV48t7N07C60Y6EMcl15JAftUCbfRDqK91v76UT5PklDqRQZh2d/7WsyDRGgJtEatggfB6Lv0GrBq7r9Fc/KeD/4sYJQiGj3RA4tGB8JSzrm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=On2ih9Un; arc=none smtp.client-ip=209.85.208.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="On2ih9Un" Received: by mail-ed1-f51.google.com with SMTP id 4fb4d7f45d1cf-6a097f5ab95so1117683a12.2 for ; Wed, 05 Aug 2026 03:01:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785924115; x=1786528915; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Auqb/Pc8pm6mSfDL4VdTlzAtlbQlPaebkU+VML+2HK0=; b=On2ih9UnRE8GHNArJjBYq5+m3bQYd5GUHrJW+xFKR6OCerVibnYkaWMdcAwWqRZ6bH wCAJFKkhR2L6SJhimmljxaObz38mI3C7uhxAYH6f/XRF8K/pyN5/DQHu0Vdat0CS9hoT 7C8vdbju8AD0tSDbpc4HdeOBtHDUMNI0RgDlN/gpKq8/wAuZvvVURl3gv/SrerZtjE/Q txIYFzS/tzU2Vg6iCGfWMDZDxSjQpHHNeHdi9QPahUwcwoR8lWly8l/EvHgJsnctdzeL zaJwCD64bvy6LgkcAsGot1eo7hLi5IhzGgKjEqLs/zMbg5no/GDNzWdEFyIM1Ug3J7G0 6S2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785924115; x=1786528915; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=Auqb/Pc8pm6mSfDL4VdTlzAtlbQlPaebkU+VML+2HK0=; b=mzcrVc1QGkZ+leix+/u6fksyeeS/K7AI+gFEqLb3k3Kg7FJ6QC/QcXBiSrouZt2ThR DtUVGay5MYiy533houb6MlICi6Jtk8cllcc1VKZiX+kRaBLOieABZz7osvlhR7Whtmbq wILxS6yAwElIHB0zJDDIWIDj4zzgZxQb1Kbo3mznf+JBL82ThNX0dA/sXVXP5DWer+nK 2ayU/p0slcmafZhNTm52qmix3X++5K5bdGDbubXiMAHCmh51RRZAh/FdMrG3bv1IHx7Y PQ4W5vchSZo9BtormMUS0uzMh3Ge2++GKCXzgLadd/o4HMYf3CW9FqLVYDhbfNVXTK+C oJIA== X-Gm-Message-State: AOJu0YxVs8SaZWTP5r/vR8WUdONiHU7VnCQc+9ZSGKt6o+IMlOrVxyTp jeX9K1r/6UW9la4mWC6m71+gweN1+pF4ZnTR6obhyVXCHfyaaPijw7Z5 X-Gm-Gg: AR+sD13O9iexxbWYaqYAhE1jMjCcT93R4epkgESuP0b+P+pin4dbjh8E7rueILkLso4 0k8JTHdrr/M5sfMxSLRBtyUSAvTJsL+9p+KPyHMZkfw0C4YBIThbRkL6qy4Pv3RXO85KRLIgm9w +EaG6Ygrqmw5rCD+U7LW1UIDrZ3HEZgAZWrh5K2o2cqwtG4NwJrIA/O/AHBeqtPR2bxm0b6hrqY 8KuEEhMGy1fVGOOwaNvAi3qulBZANdYWtFP7Spmd/b5G5a0TsyhtZUxbhCl1ZcGZ2CqGlGWaq/j sbeQP/7OayzH98AQfHTvULeML3ZXnRsIp5XsHhQPJdbVYp8bb7eeSsFEBVY0ote67TiFNOUX10n 7MLDGibL7p0jsi7NpkRVe99dAt8oWfkp6QTaRYvNsPZIep3Pk0cDGagMBAvhWyGjLIyd467RfZy EXNM+PQ32Oz56luqo2R4tGWcSsD+sWDTK6yZ6RC/zQlYfIKox2MH1X69QFc5xmHQ== X-Received: by 2002:a05:6402:4008:b0:698:5610:76e5 with SMTP id 4fb4d7f45d1cf-6a14f104110mr3334876a12.6.1785924114935; Wed, 05 Aug 2026 03:01:54 -0700 (PDT) Received: from arbab-X395.dbs.corp ([110.93.227.54]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47fec249a5fsm7344776f8f.33.2026.08.05.03.01.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Aug 2026 03:01:54 -0700 (PDT) From: Arbab Haider To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Russell King (Oracle)" , Simon Horman , Jakub Kicinski Subject: [PATCH 7.0.y 5/5] net: stmmac: fix transmit interrupt coalescing Date: Wed, 5 Aug 2026 15:01:36 +0500 Message-ID: <20260805100136.59101-5-arbabhaider649@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260805100136.59101-1-arbabhaider649@gmail.com> References: <20260805100136.59101-1-arbabhaider649@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Russell King (Oracle)" The accounting for transmit frames does not count the descriptors correctly. It uses: tx_packets = (tx_q->cur_tx + 1) - first_tx; however, these are indexes into a circular buffer, so cur_tx can be less than first_tx, and when that happens, tx_packets becomes a very large unsigned integer. When this is added to tx_q->tx_count_frames, it has the effect of reducing the count of frames, possibly causing it to also wrap to a very large unsigned integer. Fix this by using CIRC_CNT() to calculate the number of descriptors used. Signed-off-by: Russell King (Oracle) Reviewed-by: Simon Horman Link: https://patch.msgid.link/E1vuoIl-0000000Aouz-0ttb@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski [ Upstream commit dd53a0e85969c6b2a5a4e4e46ba05b3187231017 ] --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 81a6ab19a45b..0266b09f0faf 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -14,6 +14,7 @@ https://bugzilla.stlinux.com/ *******************************************************************************/ +#include #include #include #include @@ -4511,7 +4512,8 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) tx_q->tx_skbuff_dma[tx_q->cur_tx].buf_type = STMMAC_TXBUF_T_SKB; /* Manage tx mitigation */ - tx_packets = (tx_q->cur_tx + 1) - first_tx; + tx_packets = CIRC_CNT(tx_q->cur_tx + 1, first_tx, + priv->dma_conf.dma_tx_size); tx_q->tx_count_frames += tx_packets; if ((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) && priv->hwts_tx_en) @@ -4789,7 +4791,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) * This approach takes care about the fragments: desc is the first * element in case of no SG. */ - tx_packets = (entry + 1) - first_tx; + tx_packets = CIRC_CNT(entry + 1, first_tx, priv->dma_conf.dma_tx_size); tx_q->tx_count_frames += tx_packets; if ((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) && priv->hwts_tx_en) -- 2.53.0