From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 29/34] dma-direct: add support for allocation from ZONE_DMA and ZONE_DMA32 Date: Fri, 12 Jan 2018 09:42:27 +0100 Message-ID: <20180112084232.2857-30-hch@lst.de> References: <20180112084232.2857-1-hch@lst.de> Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KqTQ9gpRM5mdnZ4+PbKZZztFOTdS84gvO3UIDdU61M0=; b=C/rP/EPej76j2mvbcQC2JcaYP R/ae4h99gj4nbPHg7lH6fLCoDs+ALVgUkuwuDZKedNFD3yMSJmGb/Tyg3A8LCsF457XbYZxjVMnTX ejJDxVQRZdSHnAOr9I5H1NckA8L05trp47DMBk3CLSBlF/ZMZVaJkv2DfTk3rwVx5Q8Lfmif0kwI5 14s4DDKROGiU2eXvUDA9QV2UJWd+3nvsvJpq14e8+jTRfu7nBiNEhXGQCHvRN7HiwCZdWBgeqTh1p PLvnpp+tqVPEV62EHazJ+i9A8QzjqBRU2C3krbwCTk4fMCDGOrdDGv5Fke+3nC+VxSiOThSyuguuL In-Reply-To: <20180112084232.2857-1-hch@lst.de> Sender: sparclinux-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 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