Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933763AbeAJIEF (ORCPT + 1 other); Wed, 10 Jan 2018 03:04:05 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:39591 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933518AbeAJICC (ORCPT ); Wed, 10 Jan 2018 03:02:02 -0500 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Cc: Konrad Rzeszutek Wilk , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org, linux-cris-kernel@axis.com, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-metag@vger.kernel.org, Michal Simek , linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, patches@groups.riscv.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, Guan Xuetao , x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 28/33] dma-direct: add support for allocation from ZONE_DMA and ZONE_DMA32 Date: Wed, 10 Jan 2018 09:00:22 +0100 Message-Id: <20180110080027.13879-29-hch@lst.de> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180110080027.13879-1-hch@lst.de> References: <20180110080027.13879-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: This allows to dip into zones for lower memory if they are available. If one of the zones is not available the corresponding GFP_* flag will evaluate to 0 so they won't change anything. We provide an arch tunable for those architectures that do not use GFP_DMA for the lowest 24-bits, given that there are a few. Roughly based on the x86 code. Signed-off-by: Christoph Hellwig --- lib/dma-direct.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/lib/dma-direct.c b/lib/dma-direct.c index f04a424f91fa..8f76032ebc3c 100644 --- a/lib/dma-direct.c +++ b/lib/dma-direct.c @@ -12,6 +12,14 @@ #define DIRECT_MAPPING_ERROR 0 +/* + * Most architectures use ZONE_DMA for the first 16 Megabytes, but + * some use it for entirely different regions: + */ +#ifndef ARCH_ZONE_DMA_BITS +#define ARCH_ZONE_DMA_BITS 24 +#endif + static bool check_addr(struct device *dev, dma_addr_t dma_addr, size_t size, const char *caller) @@ -34,6 +42,12 @@ static void *dma_direct_alloc(struct device *dev, size_t size, int page_order = get_order(size); struct page *page = NULL; + /* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */ + if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS)) + gfp |= GFP_DMA; + if (dev->coherent_dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA)) + gfp |= GFP_DMA32; + /* CMA can be used only in the context which permits sleeping */ if (gfpflags_allow_blocking(gfp)) page = dma_alloc_from_contiguous(dev, count, page_order, gfp); -- 2.14.2