From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3EA3155333 for ; Tue, 1 Jul 2025 01:12:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751332346; cv=none; b=reJtEY+FWrUvuHFItxXhX/4qNjWb2RlnTU9rUmfd418As/Ku/uPqhqr6aQMUuCztNg9G+GwQ1Yvd+u1AzvkIbUP7jUJMrJe2NIx26nSgNRgjNyyw3gc4/nvi/X1L53YaE1PclFNgTNmsRw2np82XpY7JdjLcpUcsjzA8sk+ngao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751332346; c=relaxed/simple; bh=tY843qin5GxkyAW9Px3Z9B7Lx6BK7vnSrhApbVophis=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HtxRQAh1AzNZyX7f4OtC+Z3alVU/Nkz2V8smfZbBKn+t3J1QEsUiwMSiV3+ICgCVItTEUUPvI7glZwmM48gozdf6u0kt+YfxRj0Qt9epeVGjKGOGPJMwXCNohwslTEEaQFSltui72idMZKb5+RVg/rxxYlJISuT9qSWNeymmZUM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mSIztpto; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mSIztpto" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8B81C4CEE3; Tue, 1 Jul 2025 01:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751332346; bh=tY843qin5GxkyAW9Px3Z9B7Lx6BK7vnSrhApbVophis=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=mSIztpto29p1MTGCowyhydQ+juIKL8QO27b6njCX+GSZkn6hCSPbfhPA9jAS6E7GL tGHNWG2I1t7vIDNLmVUuox+OhWSLPuTOUzb/JwHuv6FQwL/hxSxIznjvyInocirCFm UrzsHYw65PUMtO6dN5CVtLjOJp+UwHjZz7de+Ma2VedMZ5xDrs8wyXkknD89QcG1X3 wY6De+bk/CL7kBUqwS71+7W326eKh9tdINTwTG0polQdwgYFiG9UHgnZOGsVs1paii 8yaGpGzZarmvwE1Xygb4OMDO95eN+n249CUuK5zRlEbdc8eXY/HsGau+w8Ut2P/ovN 1MtTVrLNNwpBg== Date: Mon, 30 Jun 2025 18:12:25 -0700 From: Jakub Kicinski To: Raju Rangoju Cc: , , , , , Subject: Re: [PATCH net v2] amd-xgbe: do not double read link status Message-ID: <20250630181225.38a67e11@kernel.org> In-Reply-To: <20250625095315.232566-1-Raju.Rangoju@amd.com> References: <20250625095315.232566-1-Raju.Rangoju@amd.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 25 Jun 2025 15:23:15 +0530 Raju Rangoju wrote: > The link status is latched low so that momentary link drops > can be detected. Avoid double-reading the status to identify > short link interruptions, unless the link was already down. Took me a minute to understand this. How about: The link status is latched low so that momentary link drops can be detected. Always double-reading the status defeats this design feature. Only double read if link was already down. > - reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); > - reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); > + if (!pdata->phy.link) { > + reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); > + if (reg < 0) > + return reg; > + > + if (reg & MDIO_STAT1_LSTATUS) > + goto skip_read; > + } > > + reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); > + if (reg < 0) > + return reg; > +skip_read: > if (pdata->en_rx_adap) { > /* if the link is available and adaptation is done, > * declare link up Don't use gotos for normal function control flow :/ reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); if (reg < 0) return reg; /* Link status is latched low so that momentary link drops * can be detected. If link was already down read again * to get the latest state. */ if (!pdata->phy.link && !(reg & MDIO_STAT1_LSTATUS)) { reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); if (reg < 0) return reg; } if (pdata->en_rx_adap) { /* if the link is available and adaptation is done, -- pw-bot: cr