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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1499BC7EE39 for ; Mon, 30 Jun 2025 11:37:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0u8GW58OtFP1vJS0kblEDCNv4tYQ/aqVCBFjiK0UBrw=; b=4x+tindYFNoyUKVeD0+k+MmFef l8wFLXX+viXaU8h1FlluBmibSOHm8FNImwsYdT1MAL3HX9IglBDu+1Rhp/Jz0AkD7O+H/lPQ/SEyf G4F1auEaZ5MELZpzwQd6WoKsVrTIUD7mvjQVvBTTrKn9+pMKYe4H7GycTHbyTZn+4aVL9ncznlK1L TULKG4+EnWvd/RkZdoQOI4aXlY2UUDxeBG1yAeuVKNAmFDcLWC4KdxN0EYm1/0boq9NnOI4w63lSg 40V29QJW9psKGXHIIuA9xqjglTC6q2wt91JZyXkROBn/gmMb0+xrdtyPSKDWCbqs/9QDNnHmArvRs N/SxwNNQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uWCpD-000000023cm-3s93; Mon, 30 Jun 2025 11:37:27 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uWCX4-00000001zxu-1CPK for linux-arm-kernel@lists.infradead.org; Mon, 30 Jun 2025 11:18:46 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 626D05C418B; Mon, 30 Jun 2025 11:18:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D31D3C4CEE3; Mon, 30 Jun 2025 11:18:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751282321; bh=/zPtV6dESq3W/I9QbMckyTu4GDaEL5TPBWwywPJ32S0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VgtoOB9vsslvh2n8Etqblw7N5AJFVaQmiRZrFoPCTCh4i54PbjXwP+1ZC7y2HP1qP AkFlhmywwhYYtPjDbPQyjbq6Twn2Wiw2r6TQKe3zb0VmytVO8KInWYObJXlIUPOxeM sxethmiiN5Ne2KMx7N2VEBGnwT7CYc6aST1+rBYyErzNzOZnQYxiIPdhqBGz+OXpeb ZnaGaoK2Eo+AKvWXrjsmmgcH3djTIuhmpxf/Y+/V1H9dxKw0ZC52nN68VnqbX7aPfm 0J8u3TdNq9laFK3F5ZA6RqfFMdme1keMqYIZ7pNdzkAMGn3g6R85/uwXYskmzCceEv d/RH8Id6k1YNA== Date: Mon, 30 Jun 2025 12:18:36 +0100 From: Simon Horman To: Alok Tiwari Cc: sgoutham@marvell.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net v2] net: thunderx: avoid direct MTU assignment after WRITE_ONCE() Message-ID: <20250630111836.GE41770@horms.kernel.org> References: <20250629051540.518216-1-alok.a.tiwari@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250629051540.518216-1-alok.a.tiwari@oracle.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250630_041842_368180_F5CFF1CB X-CRM114-Status: GOOD ( 11.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Jun 28, 2025 at 10:15:37PM -0700, Alok Tiwari wrote: ... > @@ -1589,16 +1588,18 @@ static int nicvf_change_mtu(struct net_device *netdev, int new_mtu) > return -EINVAL; > } > > - WRITE_ONCE(netdev->mtu, new_mtu); > > - if (!netif_running(netdev)) > + if (!netif_running(netdev)) { > + WRITE_ONCE(netdev->mtu, new_mtu); > return 0; > + } > > if (nicvf_update_hw_max_frs(nic, new_mtu)) { > - netdev->mtu = orig_mtu; > return -EINVAL; > } nit: curly brackets should be removed here, but see further comment below. > > + WRITE_ONCE(netdev->mtu, new_mtu); > + > return 0; > } Could this be more succinctly expressed as follows? (Completely untested!) if (netif_running(netdev) && nicvf_update_hw_max_frs(nic, new_mtu)) return -ENIVAL; WRITE_ONCE(netdev->mtu, new_mtu); return 0;