Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932922AbdL2IXS (ORCPT ); Fri, 29 Dec 2017 03:23:18 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:50934 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932252AbdL2IXM (ORCPT ); Fri, 29 Dec 2017 03:23:12 -0500 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Cc: linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, adi-buildroot-devel@lists.sourceforge.net, linux-c6x-dev@linux-c6x.org, linux-cris-kernel@axis.com, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@vger.kernel.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 50/67] swiotlb: refactor coherent buffer allocation Date: Fri, 29 Dec 2017 09:18:54 +0100 Message-Id: <20171229081911.2802-51-hch@lst.de> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171229081911.2802-1-hch@lst.de> References: <20171229081911.2802-1-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 Content-Length: 4155 Lines: 144 Factor out a new swiotlb_alloc_buffer helper that allocates DMA coherent memory from the swiotlb bounce buffer. This allows to simplify the swiotlb_alloc implemenation that uses dma_direct_alloc to try to allocate a reachable buffer first. Signed-off-by: Christoph Hellwig --- lib/swiotlb.c | 100 ++++++++++++++++++++++++++++++---------------------------- 1 file changed, 51 insertions(+), 49 deletions(-) diff --git a/lib/swiotlb.c b/lib/swiotlb.c index adb4dd0091fa..905eea6353a3 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -709,67 +709,69 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, } EXPORT_SYMBOL_GPL(swiotlb_tbl_sync_single); +static void * +swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle) +{ + phys_addr_t phys_addr; + + if (swiotlb_force == SWIOTLB_NO_FORCE) + goto out_warn; + + phys_addr = swiotlb_tbl_map_single(dev, + swiotlb_phys_to_dma(dev, io_tlb_start), + 0, size, DMA_FROM_DEVICE, 0); + if (phys_addr == SWIOTLB_MAP_ERROR) + goto out_warn; + + *dma_handle = swiotlb_phys_to_dma(dev, phys_addr); + + /* Confirm address can be DMA'd by device */ + if (*dma_handle + size - 1 > dev->coherent_dma_mask) + goto out_unmap; + + memset(phys_to_virt(phys_addr), 0, size); + return phys_to_virt(phys_addr); + +out_unmap: + dev_warn(dev, "hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n", + (unsigned long long)dev->coherent_dma_mask, + (unsigned long long)*dma_handle); + + /* + * DMA_TO_DEVICE to avoid memcpy in unmap_single. + * DMA_ATTR_SKIP_CPU_SYNC is optional. + */ + swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); +out_warn: + dev_warn(dev, + "swiotlb: coherent allocation failed, size=%zu\n", size); + dump_stack(); + return NULL; +} + void * swiotlb_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t flags) { - dma_addr_t dev_addr; - void *ret; int order = get_order(size); + void *ret; ret = (void *)__get_free_pages(flags, order); if (ret) { - dev_addr = swiotlb_virt_to_bus(hwdev, ret); - if (dev_addr + size - 1 > hwdev->coherent_dma_mask) { - /* - * The allocated memory isn't reachable by the device. - */ - free_pages((unsigned long) ret, order); - ret = NULL; + *dma_handle = swiotlb_virt_to_bus(hwdev, ret); + if (*dma_handle + size - 1 <= hwdev->coherent_dma_mask) { + memset(ret, 0, size); + return ret; } - } - if (!ret) { + /* - * We are either out of memory or the device can't DMA to - * GFP_DMA memory; fall back on map_single(), which - * will grab memory from the lowest available address range. + * The allocated memory isn't reachable by the device. */ - phys_addr_t paddr = map_single(hwdev, 0, size, - DMA_FROM_DEVICE, 0); - if (paddr == SWIOTLB_MAP_ERROR) - goto err_warn; - - ret = phys_to_virt(paddr); - dev_addr = swiotlb_phys_to_dma(hwdev, paddr); - - /* Confirm address can be DMA'd by device */ - if (dev_addr + size - 1 > hwdev->coherent_dma_mask) { - printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n", - (unsigned long long)hwdev->coherent_dma_mask, - (unsigned long long)dev_addr); - - /* - * DMA_TO_DEVICE to avoid memcpy in unmap_single. - * The DMA_ATTR_SKIP_CPU_SYNC is optional. - */ - swiotlb_tbl_unmap_single(hwdev, paddr, - size, DMA_TO_DEVICE, - DMA_ATTR_SKIP_CPU_SYNC); - goto err_warn; - } + free_pages((unsigned long) ret, order); } - *dma_handle = dev_addr; - memset(ret, 0, size); - - return ret; - -err_warn: - pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n", - dev_name(hwdev), size); - dump_stack(); - - return NULL; + return swiotlb_alloc_buffer(hwdev, size, dma_handle); } EXPORT_SYMBOL(swiotlb_alloc_coherent); @@ -1105,7 +1107,7 @@ void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, vaddr = dma_direct_alloc(dev, size, dma_handle, gfp, attrs); if (!vaddr) - vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, gfp); + vaddr = swiotlb_alloc_buffer(dev, size, dma_handle); return vaddr; } -- 2.14.2