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 A2F7DC4332F for ; Tue, 20 Dec 2022 14:18:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=pYc6O2BnhKB/tEM5XQwX5NhdV2qRRthBNd9rapj02CQ=; b=WC+0NT/7GZ9W+z pZNVer46U4JHvDRVeuzg2uuVyBve7BNhSuOQd1zfO66VGZ5IyPnxncIvBT5mM7b5XwfbLstuDFY0p XoCfZWikNKXOdHB17MLL/8BBxgXhHq4GYe9B21bn84UjEXxh5/FQUXDYnuE5TAha7eUQyVCNJSTSI 6nQm5Wnu6WavDTb91ULlABIgK8tWuxkQl2U+gwAEfwPOpJtMYhGmOzhZA2eDVEKSdUT7q4RZHbRWY dXYFaNuqk5Kp9nCw3oVyhkuiUuLReeDtQf4EUwWYdKtAMfbuC4dDf57tIDk7YYWK0THGIkGFckS9W plOLfh2ynIk77buHfgFQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p7dQa-00GZ6G-Gt; Tue, 20 Dec 2022 14:17:08 +0000 Received: from msg-2.mailo.com ([213.182.54.12]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p7dQL-00GYxQ-6t for linux-arm-kernel@lists.infradead.org; Tue, 20 Dec 2022 14:16:55 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailo.com; s=mailo; t=1671545803; bh=KFy9i0U+bz5w8ZNQPETAfc303KW3oDGaFSwUS0I9Z7Y=; h=X-EA-Auth:Date:From:To:Cc:Subject:Message-ID:MIME-Version: Content-Type; b=Afvz7mrsiDCgrGiDOYGru1q/4CJKU+h4mzfJJv9UqrwG4ed3Qi3AVAFKJIg4/7qee ClaTK7yGkMDRp5fmDVp9cUXfOH0XmGZ7NVxPyVzUi58fuBJ4xSS2110W6Uiq+KeT3p pQy4hAox9nBiqXnb+3sP6G2hYNF+lLAHQW4iEIfM= Received: by b-5.in.mailobj.net [192.168.90.15] with ESMTP via ip-206.mailobj.net [213.182.55.206] Tue, 20 Dec 2022 15:16:43 +0100 (CET) X-EA-Auth: ht9cxGNE36MfwDJyGTplQ3KyBpF29jM0Yl/k5AFuB85lfHkYRBCHHBwHRBFEOuzVkAcq944OAyB/kI1/c0sM/TPaAgdnykvt Date: Tue, 20 Dec 2022 19:46:32 +0530 From: Deepak R Varma To: Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Praveen Kumar , Saurabh Singh Sengar , Julia Lawall , drv@mailo.com Subject: [PATCH v2] ARM/dma-mapping: use kvcalloc for fallback memory allocation need Message-ID: MIME-Version: 1.0 Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221220_061653_677981_4B8E8AC3 X-CRM114-Status: GOOD ( 13.50 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Current conditional determination of whether to use kzalloc or vzalloc has known issues such as "indefinite retry" when less than PAGE_SIZE memory is needed, but is unavailable. This LWN article [1] describes these issues in greater detail. Use helper function kvcalloc() instead which is more efficient in terms of performance and security. [1] https://lwn.net/Articles/711653/ This patch proposal is based on following Coccinelle warning using the kvmalloc.cocci semantic patch. arch/arm/mm/dma-mapping.c:858:28-29: WARNING opportunity for kvmalloc The semantic patch suggests using kvzalloc() helper function, however, this patch proposes to use kvcalloc instead. kvcalloc() helper function uses 2-factor argument form which is better from a security perspective as described in the following KSPP project commit. Commit 4e3fd7217105 ("wireguard: ratelimiter: use kvcalloc() instead of kvzalloc()") Signed-off-by: Deepak R Varma --- Changes in v2: 1. Update patch subject to use kvcalloc 2. Use kvcalloc instead of kvzalloc helper function. Revise the patch proposal and the patch description accordingly. arch/arm/mm/dma-mapping.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index c135f6e37a00..35092ecd30e1 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -851,14 +851,10 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, { struct page **pages; int count = size >> PAGE_SHIFT; - int array_size = count * sizeof(struct page *); int i = 0; int order_idx = 0; - if (array_size <= PAGE_SIZE) - pages = kzalloc(array_size, GFP_KERNEL); - else - pages = vzalloc(array_size); + pages = kvcalloc(count, sizeof(struct page *), GFP_KERNEL); if (!pages) return NULL; -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel