From nobody Fri Oct 2 07:45:42 2026 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) (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 A960D3C73F6 for ; Mon, 3 Aug 2026 23:47:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.175 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785800875; cv=none; b=V3DHVxfNLUIjx+AmG7+De8j3IPAK3mi1AudGgj5Dam9Bkli/dh/FnD/Btf7ze+3pCofa9APft3oOgGOPVPjeCC4IiAZhwebC5MIx9lEkl9vLLQzsJIiNRACxeuEM0zCvpbSzrTAyoLTtR6tioX0jw+unGAw9Crd8VaXcvyv9Z1I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785800875; c=relaxed/simple; bh=eB+ze/+u7thR9be6FtIVrOzuGSSTupcYFQmfVu3l1d8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=d/jmTJ7GAn1/Pk284TuHN8NcSdY4GcHXFIPH0pf86sR2rCIw9C9GMxWnxxnRC5pHfos0AahPbs80udc3xlzhvsno0DXVnvwHrsvKEQMYPIGFq9bYOhyP4AP1IEg2f73OHdU/JEHbfM9o2DgQZwkTl6b/5cP6RkhcvZDMj8GmfkI= 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=lQBNEMR/; arc=none smtp.client-ip=209.85.210.175 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="lQBNEMR/" Received: by mail-pf1-f175.google.com with SMTP id d2e1a72fcca58-84847482584so303076b3a.0 for ; Mon, 03 Aug 2026 16:47:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785800861; x=1786405661; darn=vger.kernel.org; h=cc:to:message-id:content-transfer-encoding:content-type :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to:content-type; bh=ZN2PrMjeC/rF7ocz4YocvO7Rr3+RP+K43ZmGxuO2IKg=; b=lQBNEMR/GOY7amJFkU9BRmd+CZ5jiQ78lnIQNgZWAJJBemdva3r+mIWyfAIxCumPJq ReIs2aL4KDCA9o3ySS3ulkfs4z94rqU/JL1ohKgKxz/ODzB9zNQDXXNqQZYnb2TK54dp p15IXsxjoOUMZpnfnIikAPCNaWmFhx+hJlALH7E9sqhqk7mY/AEOhBUMd7FoVS/yfBWL X3XeWdAmP0M7+KlcgEuikGMimodd5jrmZ7nmR7h0rtpvh9ge7zbGFxUi9SHV7tr8smrJ cBeKqoVDRLX3TImyjWLdSfbzxFLMQYhg2tSm+SJNFKbgclYOmMUl0uscR5PXmdQH3UwJ wpxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785800861; x=1786405661; h=cc:to:message-id:content-transfer-encoding:content-type :mime-version:subject:date:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to:content-type; bh=ZN2PrMjeC/rF7ocz4YocvO7Rr3+RP+K43ZmGxuO2IKg=; b=jLdSwgTj7ts6v74pj4PcEAUsYiWv/xOaVLd0bGebSOPSzA6l4/ZGtcimkT1GSWpQio 70utEtL3+o+Q8ohhTnEyFLvQROOdnERPU/Qq+kMp2AbzQ2XaY2xhbgzHqpvudBU7geaX kFAdB5cVicHyJXunqi1N6UhxwBZ6zqnyZU09ra/KdBtiiWSNg7guYRVeRz4jp3Lole04 TMsNMHWVnz5DThJFyUsJFEz0hhN+pFjtqdPAIiLiK3D1G7yNWmHdU8BO8Zi0DgHTYEds 3avkaq7qbnQw0yoyIi86wiD9fPGQMdgS5vmSGyCkP+OSC67ts2rsSe5bDGuAXi6wgFbl px5Q== X-Forwarded-Encrypted: i=1; AHgh+RrH7sDtmsS1tLgvBMofbsryxh13JWbaVW/MBLV9JCz3CBxhgIqSkst9vBjIAkkRFKtI0txd1s0pZDSfnAc=@vger.kernel.org X-Gm-Message-State: AOJu0Yy6JflxCksRf+r6BV+CwiOgUUdEfpJVwQfcwxiHwAfS+8Awofgl yxx/0yghYLN9W8BuxV8O0eBjPfxrA1DZSI9siLuilyeVV1gHB8ohtdrg X-Gm-Gg: AR+sD11I6cLYdmxTYAyxkZokgC7kEpD46akb/U0nq7cT93XPzm0OUsNfjoMR+Ve9Dlr oANgTCQx2H1yRwbsHuItds9Urb8We3a5bRnYFpGmJaRFNJIT/1gP2QSZxT12InKtYNDUshnS0O8 xrg/sDmL5+21TmpaXAumyw6HwPmFWErCzEW0rXrCqKhGNAG1rwPFpzlCq5mH+JK4kDHC/C5jK71 S0MsmBuZDfkK/O+KEYFVR2UgS4YP1S47bxSYR1ub27yvEsGSeAQPcQPNEWooyaO/WRgSYAeTT4s 4SF0XL7zrZZHLIS/3rNwNj5J6ighlupdGzoSyQbahoTzuCUc4JWACMAII0hMkdKV2LTCfY5gWBq eO5Y7aapqT7t6c90vd4PPpoEjVs6VSrr3aaWSCk9F4tTC7Bv5L52uR5oY+Fz8sQK2i8jFioTu1n OhzCsEdCNRCTRYvr7aiRY93JcT9TqwKX9cM30xGfvraiZRLPcTE4TNhZg= X-Received: by 2002:a05:6a00:a90c:b0:848:2f58:e1e9 with SMTP id d2e1a72fcca58-84f1cbc930dmr1257604b3a.36.1785800860784; Mon, 03 Aug 2026 16:47:40 -0700 (PDT) Received: from localhost ([2a03:2880:ff:8::]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84edbe7a243sm4263667b3a.24.2026.08.03.16.47.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Aug 2026 16:47:39 -0700 (PDT) From: Bobby Eshleman Date: Mon, 03 Aug 2026 16:47:29 -0700 Subject: [PATCH net v3] net/mlx5e: fix BQL reset on SQ re-activation Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260803-mlx5-bql-v3-1-a30d4c66fe1d@meta.com> X-B4-Tracking: v=1; b=H4sIAJEocWoC/2XMQQ6DIBBA0auQWTsNUBF01Xs0XSCMlaRqC4bYG O/ehJVJ1z//7ZAoBkrQsR0i5ZDCMkPHrhUDN9r5SRg8dAwklw3X0uD02hT2nxeamri0ytaNM1A xeEcawlaoO8y0wqNiMIa0LvFb+CxK+peyQIFta7nttSZP+jbRai9umYqR5flrT59Egc4P0ihSp vHD6TuO4wfg1Jyt3AAAAA== X-Change-ID: 20260728-mlx5-bql-84e02a5a46c8 To: Saeed Mahameed , Tariq Toukan , Mark Bloch , Leon Romanovsky , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Dragos Tatulea , Mina Almasry Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Bobby Eshleman X-Mailer: b4 0.14.3 From: Bobby Eshleman mlx5e_queue_start() deactivates and re-activates all channels but closes only the queue being restarted. mlx5e_activate_txqsq() then unconditionally calls netdev_tx_reset_queue(), zeroing the BQL counters of channels that kept their in-flight TX WQEs. The next completion then over-charges and trips the BUG_ON() in dql_completed(): kernel BUG at lib/dynamic_queue_limits.c:99! RIP: 0010:dql_completed+0x23d/0x280 Call Trace: mlx5e_poll_tx_cq+0x668/0xa60 mlx5e_napi_poll+0x5b/0x7b0 net_rx_action+0x15a/0x580 Reset BQL only when the SQ has no bytes in flight (sq->cc =3D=3D sq->pc). In the case that reset is skipped, the outstanding WQEs will eventually complete and rebalance the dql. The dql->limit is carried across the reset. Fixes: b2588ea40ec9 ("net/mlx5e: Implement queue mgmt ops and single channe= l swap") Signed-off-by: Bobby Eshleman Reviewed-by: Tariq Toukan --- Changes in v3: - Sample sq->cc/sq->pc before setting MLX5E_SQ_STATE_ENABLED, so a concurrent mlx5e_poll_tx_cq() cannot un-charge BQL between the check and netdev_tx_reset_queue() (Sashiko: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260729-mlx5-bql-v2-= 1-cdf285e586df@meta.com) - Link to v2: https://lore.kernel.org/r/20260729-mlx5-bql-v2-1-cdf285e586df= @meta.com Changes in v2: - remove misleading comment (Tariq) - Link to v1: https://lore.kernel.org/r/20260728-mlx5-bql-v1-1-99a0ab77ede7= @meta.com --- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/ne= t/ethernet/mellanox/mlx5/core/en_main.c index 7d47a1da8b6b..f0407a850ea8 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -1939,8 +1939,10 @@ int mlx5e_open_txqsq(struct mlx5e_channel *c, u32 ti= sn, int txq_ix, void mlx5e_activate_txqsq(struct mlx5e_txqsq *sq) { sq->txq =3D netdev_get_tx_queue(sq->netdev, sq->txq_ix); + /* Reset BQL only when the SQ has no bytes in flight. */ + if (sq->cc =3D=3D sq->pc) + netdev_tx_reset_queue(sq->txq); set_bit(MLX5E_SQ_STATE_ENABLED, &sq->state); - netdev_tx_reset_queue(sq->txq); netif_tx_start_queue(sq->txq); netif_queue_set_napi(sq->netdev, sq->txq_ix, NETDEV_QUEUE_TYPE_TX, sq->cq= .napi); } --- base-commit: d1000fd7995e51deec872d154e0a40d82f7a539f change-id: 20260728-mlx5-bql-84e02a5a46c8 Best regards, --=20 Bobby Eshleman