Makes use of the same atomic pool from DMA, and skips kernel page mapping which can involve sleep'able operations at allocating a kernel page table.
Signed-off-by: Hiroshi Doyu hdoyu@nvidia.com --- arch/arm/mm/dma-mapping.c | 30 +++++++++++++++++++++++++----- 1 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 7ab016b..433312a 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1063,7 +1063,6 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, struct page **pages; int count = size >> PAGE_SHIFT; int array_size = count * sizeof(struct page *); - int err;
if ((array_size <= PAGE_SIZE) || (gfp & GFP_ATOMIC)) pages = kzalloc(array_size, gfp); @@ -1072,9 +1071,20 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, if (!pages) return NULL;
- err = __alloc_fill_pages(&pages, count, gfp); - if (err) - goto error + if (gfp & GFP_ATOMIC) { + struct page *page; + int i; + void *addr = __alloc_from_pool(size, &page); + if (!addr) + goto error; + + for (i = 0; i < count; i++) + pages[i] = page + i; + } else { + int err = __alloc_fill_pages(&pages, count, gfp); + if (err) + goto error; + }
return pages;
@@ -1091,9 +1101,15 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t s int count = size >> PAGE_SHIFT; int array_size = count * sizeof(struct page *); int i; + + if (__free_from_pool(page_address(pages[0]), size)) + goto out; + for (i = 0; i < count; i++) if (pages[i]) __free_pages(pages[i], 0); + +out: if ((array_size <= PAGE_SIZE) || __in_atomic_pool(page_address(pages[0]), size)) kfree(pages); @@ -1221,6 +1237,9 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, if (*handle == DMA_ERROR_CODE) goto err_buffer;
+ if (gfp & GFP_ATOMIC) + return page_address(pages[0]); + if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) return pages;
@@ -1279,7 +1298,8 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, return; }
- if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) { + if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs) || + !__in_atomic_pool(cpu_addr, size)) { unmap_kernel_range((unsigned long)cpu_addr, size); vunmap(cpu_addr); }