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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C99C2C433E6 for ; Wed, 22 Jul 2020 11:28:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A8B520771 for ; Wed, 22 Jul 2020 11:28:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="STIqoXPB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A8B520771 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 16ACD6B0003; Wed, 22 Jul 2020 07:28:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 11B7F6B0005; Wed, 22 Jul 2020 07:28:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 030836B0006; Wed, 22 Jul 2020 07:28:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0151.hostedemail.com [216.40.44.151]) by kanga.kvack.org (Postfix) with ESMTP id E24416B0003 for ; Wed, 22 Jul 2020 07:28:41 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 76BBC1839764D for ; Wed, 22 Jul 2020 11:28:41 +0000 (UTC) X-FDA: 77065489242.12.back65_2f1808f26f35 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id 0112C1A56C723 for ; Wed, 22 Jul 2020 11:27:44 +0000 (UTC) X-HE-Tag: back65_2f1808f26f35 X-Filterd-Recvd-Size: 2054 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Wed, 22 Jul 2020 11:27:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=gzjIpPTE0BOMS+w0TJyJ1YeBbYxcBd9ssbvwpStcd2Y=; b=STIqoXPBQrh67Rq3RQ2a3HH1Gz vMo8BeblxQGh2iST1cDC83ADsBLlr3xiRZCjKXMNAX92u0n3ssD72DAz/ssd5dJNLW0XK0VPGSunn iqurWIoRNfM1jCVFHWpjCEub3LDY50gAt9YlH/tk/9bHFzJizIXw+5icxqyjAs1O5FydgbOwXOvQJ oYDlawn1aaKXnSDcaxJ1jm3qAe4hx57G4cMOnMf9DPjqkTtM7QYd85V0713584BP3v8jn4CK7+Sps bkGNeMaGwQLoVpfHSy0z0QauBL5Y3CNq3Oojxc8ON4DbjCb1wWqm56SQq8dgOUJ83xT853upRlrjY BIbMacUg==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyCuR-0005Ao-1m; Wed, 22 Jul 2020 11:27:40 +0000 Date: Wed, 22 Jul 2020 12:27:38 +0100 From: Matthew Wilcox To: qiang.zhang@windriver.com Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/dmapool.c: add lock protect in dma_pool_destroy Message-ID: <20200722112738.GN15516@casper.infradead.org> References: <20200722090516.28829-1-qiang.zhang@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200722090516.28829-1-qiang.zhang@windriver.com> X-Rspamd-Queue-Id: 0112C1A56C723 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jul 22, 2020 at 05:05:16PM +0800, qiang.zhang@windriver.com wrote: > When traversing "pool->page" linked list, to prevent possible > other path operations this list, causing it to be destroyed, we > should add lock protect for this list in dma_pool_destroy func. The pool is being destroyed. If somebody else is trying to allocate from it while it's in the middle of being destroyed, there is a larger problem to solve, and it can't be solved in the dmapool code.