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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59279C00140 for ; Thu, 18 Aug 2022 19:27:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343815AbiHRT1J (ORCPT ); Thu, 18 Aug 2022 15:27:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235563AbiHRT1I (ORCPT ); Thu, 18 Aug 2022 15:27:08 -0400 Received: from vps0.lunn.ch (vps0.lunn.ch [185.16.172.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9D2FC9EA8 for ; Thu, 18 Aug 2022 12:27:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=YWB8xh/py5bH9cGdR1c68GrZdItJitpeqZsvSRtjWDI=; b=HFZzIyEFtRz7ntbw8sXN1fx8XB JDNpCejVsZUFwm4AMHkDiMjKmxhwPgYp/batR8sQ7517utbVJ4IvT6APcAROCt3XSydt0WGZSs6DM rZtcsC3KpE86oYa5ktG9RAm5RImGHqL+YcRcTqRzDEWw0AWZUVUxLWQ7q/ODQRpaSlFc=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1oOlAY-00Dpkb-0P; Thu, 18 Aug 2022 21:27:06 +0200 Date: Thu, 18 Aug 2022 21:27:05 +0200 From: Andrew Lunn To: Sergei Antonov Cc: netdev@vger.kernel.org, Jakub Kicinski , Vladimir Oltean Subject: Re: [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas Message-ID: References: <20220818182948.931712-1-saproj@gmail.com> <20220818182948.931712-2-saproj@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220818182948.931712-2-saproj@gmail.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Aug 18, 2022 at 09:29:48PM +0300, Sergei Antonov wrote: > Fix the warning poping up after bringing the link down, then up: > ip link set dev eth0 down > ip link set dev eth0 up > > WARNING: CPU: 0 PID: 55 at kernel/dma/debug.c:570 add_dma_entry+0x204/0x2ec > DMA-API: moxart-ethernet 92000000.mac: cacheline tracking EEXIST, overlapping mappings aren't supported > CPU: 0 PID: 55 Comm: ip Not tainted 5.19.0+ #57 > Hardware name: Generic DT based system > unwind_backtrace from show_stack+0x10/0x14 > show_stack from dump_stack_lvl+0x34/0x44 > dump_stack_lvl from __warn+0xbc/0x1f0 > __warn from warn_slowpath_fmt+0x94/0xc8 > warn_slowpath_fmt from add_dma_entry+0x204/0x2ec > add_dma_entry from dma_map_page_attrs+0x110/0x328 > dma_map_page_attrs from moxart_mac_open+0x134/0x320 > moxart_mac_open from __dev_open+0x11c/0x1ec > __dev_open from __dev_change_flags+0x194/0x22c > __dev_change_flags from dev_change_flags+0x14/0x44 > dev_change_flags from devinet_ioctl+0x6d4/0x93c > devinet_ioctl from inet_ioctl+0x1ac/0x25c > > Unmap RX memory areas in moxart_mac_stop(), so that moxart_mac_open() > will map them anew instead of double-mapping. To avoid code duplication, > create a new function moxart_mac_unmap_rx(). Nullify unmapped pointers to > prevent double-unmapping (ex: moxart_mac_stop(), then moxart_remove()). This makes the code symmetric, which is good. However, moxart_mac_free_memory() will also free the descriptors, which is not required. moxart_remove() should undo what the probe did, nothing more. Andrew