From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756472AbeEJEkU (ORCPT ); Thu, 10 May 2018 00:40:20 -0400 Received: from mail-sn1nam02on0108.outbound.protection.outlook.com ([104.47.36.108]:38806 "EHLO NAM02-SN1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750854AbeEJEkR (ORCPT ); Thu, 10 May 2018 00:40:17 -0400 Authentication-Results: spf=pass (sender IP is 117.103.190.41) smtp.mailfrom=sony.com; kvack.org; dkim=none (message not signed) header.d=none;kvack.org; dmarc=bestguesspass action=none header.from=sony.com; From: To: , , , , CC: , , , , Subject: RE: Are media drivers abusing of GFP_DMA? - was: Re: [LSF/MM TOPIC NOTES] x86 ZONE_DMA love Thread-Topic: Are media drivers abusing of GFP_DMA? - was: Re: [LSF/MM TOPIC NOTES] x86 ZONE_DMA love Thread-Index: AQHT5ItRb0y5QFw5Gk+kOQy+y2CJ9KQoXEaA Date: Thu, 10 May 2018 04:39:58 +0000 Message-ID: <02699364973B424C83A42A84B04FDA854A3893@JPYOKXMS113.jp.sony.com> References: <20180426215406.GB27853@wotan.suse.de> <20180505130815.53a26955@vento.lan> In-Reply-To: <20180505130815.53a26955@vento.lan> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [2001:cf8:1:aec:0:dddd:260a:38bf] Content-Type: text/plain; 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Before doing that, > better to check if what we have on media is are valid use cases for it, > or > if it is there just due to some misunderstanding (or because it was > copied from some other code). > > Hans de Goede sent us today a patch stopping abuse at gspca, and I'm > also posting today two other patches meant to stop abuse of it on USB > drivers. Still, there are 4 platform drivers using it: > > $ git grep -l -E "GFP_DMA\\b" drivers/media/ > drivers/media/platform/omap3isp/ispstat.c > drivers/media/platform/sti/bdisp/bdisp-hw.c > drivers/media/platform/sti/hva/hva-mem.c > drivers/media/spi/cxd2880-spi.c > > Could you please check if GFP_DMA is really needed there, or if it is > just because of some cut-and-paste from some other place? About drivers/media/spi/cxd2880-spi.c, we referred to kmalloc of driver/spi/spi.c spi_write_then_read() function and made this code. Regards, Takiguchi