From patchwork Tue Jun 7 18:44:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Battersby X-Patchwork-Id: 12872239 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03B62C43334 for ; Tue, 7 Jun 2022 18:44:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 94B236B0085; Tue, 7 Jun 2022 14:44:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8FA806B0087; Tue, 7 Jun 2022 14:44:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7C2F56B0088; Tue, 7 Jun 2022 14:44:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 6DDF66B0085 for ; Tue, 7 Jun 2022 14:44:21 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 4E0C620CAB for ; Tue, 7 Jun 2022 18:44:21 +0000 (UTC) X-FDA: 79552315122.06.4CEA58E Received: from mail.cybernetics.com (mail.cybernetics.com [173.71.130.66]) by imf21.hostedemail.com (Postfix) with ESMTP id 6D9541C006F for ; Tue, 7 Jun 2022 18:44:04 +0000 (UTC) X-ASG-Debug-ID: 1654627459-1cf43917f3396680001-v9ZeMO Received: from cybernetics.com ([10.10.4.126]) by mail.cybernetics.com with ESMTP id ytKMQdwzzCTN1huP; Tue, 07 Jun 2022 14:44:19 -0400 (EDT) X-Barracuda-Envelope-From: tonyb@cybernetics.com X-ASG-Whitelist: Client DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=cybernetics.com; s=mail; bh=ko90FEQrFc3kr/EXmZEbhsh++NujIvq49Z2hdvGupnI=; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:References:Cc:To:From: Content-Language:Subject:MIME-Version:Date:Message-ID; b=WUGhF+zc7hcw6JoFhMVn sGaBwqMKrtT0LAsXqUcUj76iU06x+W8kn/yVArt8p4dHAKYUv4FvRp/bnqdKNITJ8eZ4h4+G4cdWa MiUopTVPkmkKCknVE11Zis2M2WKnboszBLWCavFSHLU31NMgSYjzMIvvxF7fzNbz4pg+2PoWvM= Received: from [10.157.2.224] (HELO [192.168.200.1]) by cybernetics.com (CommuniGate Pro SMTP 7.1.1) with ESMTPS id 11859456; Tue, 07 Jun 2022 14:44:19 -0400 Message-ID: <06f83492-1eaf-16c4-31b0-1f148995ee59@cybernetics.com> Date: Tue, 7 Jun 2022 14:44:18 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: [PATCH v6 07/11] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Content-Language: en-US X-ASG-Orig-Subj: [PATCH v6 07/11] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled From: Tony Battersby To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: iommu@lists.linux-foundation.org, kernel-team@fb.com, Matthew Wilcox , Keith Busch , Andy Shevchenko , Robin Murphy , Tony Lindgren References: <340ff8ef-9ff5-7175-c234-4132bbdfc5f7@cybernetics.com> In-Reply-To: <340ff8ef-9ff5-7175-c234-4132bbdfc5f7@cybernetics.com> X-Barracuda-Connect: UNKNOWN[10.10.4.126] X-Barracuda-Start-Time: 1654627459 X-Barracuda-URL: https://10.10.4.122:443/cgi-mod/mark.cgi X-Barracuda-BRTS-Status: 1 X-Virus-Scanned: by bsmtpd at cybernetics.com X-Barracuda-Scan-Msg-Size: 1450 X-Rspam-User: Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=cybernetics.com header.s=mail header.b=WUGhF+zc; dmarc=pass (policy=none) header.from=cybernetics.com; spf=pass (imf21.hostedemail.com: domain of "btv1==15738f5bfcd==tonyb@cybernetics.com" designates 173.71.130.66 as permitted sender) smtp.mailfrom="btv1==15738f5bfcd==tonyb@cybernetics.com" X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 6D9541C006F X-Stat-Signature: ohpzide5cyjrgeody1bzxxx1sw7twot4 X-HE-Tag: 1654627444-466849 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: There are two cases: 1) In the normal case that the memory is being freed correctly, then DMAPOOL_DEBUG will memset the memory anyway, so speed thing up by avoiding a double-memset of the same memory. 2) In the abnormal case that DMAPOOL_DEBUG detects that a driver passes incorrect parameters to dma_pool_free() (e.g. double-free, invalid free, mismatched vaddr/dma, etc.), then that is a kernel bug, and we don't want to clear the passed-in possibly-invalid memory pointer because we can't be sure that the memory is really free. So don't clear it just because init_on_free=1. Signed-off-by: Tony Battersby --- mm/dmapool.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index facdb3571976..44038089a41a 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -406,8 +406,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) } offset = vaddr - page->vaddr; - if (want_init_on_free()) - memset(vaddr, 0, pool->size); #ifdef DMAPOOL_DEBUG if ((dma - page->dma) != offset) { spin_unlock_irqrestore(&pool->lock, flags); @@ -452,6 +450,9 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) goto freelist_corrupt; } memset(vaddr, POOL_POISON_FREED, pool->size); +#else + if (want_init_on_free()) + memset(vaddr, 0, pool->size); #endif page->in_use--;