From 0176adb004065d6815a8e67946752df4cd947c5b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 9 Jan 2018 22:15:30 +0100 Subject: swiotlb: refactor coherent buffer allocation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Christian König --- lib/swiotlb.c | 122 +++++++++++++++++++++++++++++++--------------------------- 1 file changed, 65 insertions(+), 57 deletions(-) (limited to 'lib') diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 1a147f1354a1..0039b7c5e690 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -709,75 +709,79 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, } EXPORT_SYMBOL_GPL(swiotlb_tbl_sync_single); -void * -swiotlb_alloc_coherent(struct device *hwdev, size_t size, - dma_addr_t *dma_handle, gfp_t flags) +static inline bool dma_coherent_ok(struct device *dev, dma_addr_t addr, + size_t size) { - bool warn = !(flags & __GFP_NOWARN); - dma_addr_t dev_addr; - void *ret; - int order = get_order(size); - u64 dma_mask = DMA_BIT_MASK(32); + u64 mask = DMA_BIT_MASK(32); - if (hwdev && hwdev->coherent_dma_mask) - dma_mask = hwdev->coherent_dma_mask; + if (dev && dev->coherent_dma_mask) + mask = dev->coherent_dma_mask; + return addr + size - 1 <= mask; +} - ret = (void *)__get_free_pages(flags, order); - if (ret) { - dev_addr = swiotlb_virt_to_bus(hwdev, ret); - if (dev_addr + size - 1 > dma_mask) { - /* - * The allocated memory isn't reachable by the device. - */ - free_pages((unsigned long) ret, order); - ret = NULL; - } - } - 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. - */ - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE, - warn ? 0 : DMA_ATTR_NO_WARN); - if (paddr == SWIOTLB_MAP_ERROR) - goto err_warn; +static void * +swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle, + unsigned long attrs) +{ + phys_addr_t phys_addr; - ret = phys_to_virt(paddr); - dev_addr = swiotlb_phys_to_dma(hwdev, paddr); + if (swiotlb_force == SWIOTLB_NO_FORCE) + goto out_warn; - /* Confirm address can be DMA'd by device */ - if (dev_addr + size - 1 > dma_mask) { - printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n", - (unsigned long long)dma_mask, - (unsigned long long)dev_addr); + 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_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; - } - } + *dma_handle = swiotlb_phys_to_dma(dev, phys_addr); + if (dma_coherent_ok(dev, *dma_handle, size)) + goto out_unmap; - *dma_handle = dev_addr; - memset(ret, 0, size); + memset(phys_to_virt(phys_addr), 0, size); + return phys_to_virt(phys_addr); - return ret; +out_unmap: + dev_warn(dev, "hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n", + (unsigned long long)(dev ? dev->coherent_dma_mask : 0), + (unsigned long long)*dma_handle); -err_warn: - if (warn && printk_ratelimit()) { - pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n", - dev_name(hwdev), size); + /* + * 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: + if ((attrs & DMA_ATTR_NO_WARN) && printk_ratelimit()) { + 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) +{ + int order = get_order(size); + unsigned long attrs = (flags & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0; + void *ret; + + ret = (void *)__get_free_pages(flags, order); + if (ret) { + *dma_handle = swiotlb_virt_to_bus(hwdev, ret); + if (dma_coherent_ok(hwdev, *dma_handle, size)) { + memset(ret, 0, size); + return ret; + } + free_pages((unsigned long)ret, order); + } + + return swiotlb_alloc_buffer(hwdev, size, dma_handle, attrs); +} EXPORT_SYMBOL(swiotlb_alloc_coherent); static bool swiotlb_free_buffer(struct device *dev, size_t size, @@ -1103,6 +1107,10 @@ void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, { void *vaddr; + /* temporary workaround: */ + if (gfp & __GFP_NOWARN) + attrs |= DMA_ATTR_NO_WARN; + /* * Don't print a warning when the first allocation attempt fails. * swiotlb_alloc_coherent() will print a warning when the DMA memory @@ -1112,7 +1120,7 @@ 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, attrs); return vaddr; } -- cgit v1.2.3-59-g8ed1b