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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 4F40FC43445 for ; Tue, 14 Jul 2020 12:40:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28A3D22472 for ; Tue, 14 Jul 2020 12:40:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728534AbgGNMkI (ORCPT ); Tue, 14 Jul 2020 08:40:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:54810 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728461AbgGNMkB (ORCPT ); Tue, 14 Jul 2020 08:40:01 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id B6D5AB02E; Tue, 14 Jul 2020 12:40:02 +0000 (UTC) From: Nicolas Saenz Julienne To: hch@lst.de, linux-kernel@vger.kernel.org, Marek Szyprowski , Robin Murphy Cc: linux-rpi-kernel@lists.infradead.org, jeremy.linton@arm.com, Nicolas Saenz Julienne , iommu@lists.linux-foundation.org Subject: [PATCH v2 3/4] dma-pool: Introduce dma_guess_pool() Date: Tue, 14 Jul 2020 14:39:27 +0200 Message-Id: <20200714123928.8581-4-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714123928.8581-1-nsaenzjulienne@suse.de> References: <20200714123928.8581-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org dma-pool's dev_to_pool() creates the false impression that there is a way to grantee a mapping between a device's DMA constraints and an atomic pool. It tuns out it's just a guess, and the device might need to use an atomic pool containing memory from a 'safer' (or lower) memory zone. To help mitigate this, introduce dma_guess_pool() which can be fed a device's DMA constraints and atomic pools already known to be faulty, in order for it to provide an better guess on which pool to use. Signed-off-by: Nicolas Saenz Julienne --- kernel/dma/pool.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 318035e093fb..5b9eaa2b498d 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -203,7 +203,7 @@ static int __init dma_atomic_pool_init(void) } postcore_initcall(dma_atomic_pool_init); -static inline struct gen_pool *dev_to_pool(struct device *dev) +static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev) { u64 phys_mask; gfp_t gfp; @@ -217,10 +217,30 @@ static inline struct gen_pool *dev_to_pool(struct device *dev) return atomic_pool_kernel; } +static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool) +{ + if (bad_pool == atomic_pool_kernel) + return atomic_pool_dma32 ? : atomic_pool_dma; + + if (bad_pool == atomic_pool_dma32) + return atomic_pool_dma; + + return NULL; +} + +static inline struct gen_pool *dma_guess_pool(struct device *dev, + struct gen_pool *bad_pool) +{ + if (bad_pool) + return dma_get_safer_pool(bad_pool); + + return dma_guess_pool_from_device(dev); +} + void *dma_alloc_from_pool(struct device *dev, size_t size, struct page **ret_page, gfp_t flags) { - struct gen_pool *pool = dev_to_pool(dev); + struct gen_pool *pool = dma_guess_pool(dev, NULL); unsigned long val; void *ptr = NULL; @@ -249,7 +269,7 @@ void *dma_alloc_from_pool(struct device *dev, size_t size, bool dma_free_from_pool(struct device *dev, void *start, size_t size) { - struct gen_pool *pool = dev_to_pool(dev); + struct gen_pool *pool = dma_guess_pool(dev, NULL); if (!pool || !gen_pool_has_addr(pool, (unsigned long)start, size)) return false; -- 2.27.0