| Message ID | 1345702229-9539-5-git-send-email-hdoyu@nvidia.com |
|---|---|
| State | New |
| Headers | show |
Hi Hiroshi, On Thursday, August 23, 2012 8:10 AM Hiroshi Doyu wrote: > 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; > I've read the whole code and it looks that it starts to become a little spaghetti - there are too many places altered by those atomic changes and it is hard to follow the logic at the first sight. IMHO it will be better to add a following function: static void *__iommu_alloc_atomic(struct device *dev, size_t size, dma_addr_t *handle) { struct page *page, **pages; int count = size >> PAGE_SHIFT; int array_size = count * sizeof(struct page *); void *addr; int i; pages = kzalloc(array_size, gfp); if (!pages) return NULL; addr = __alloc_from_pool(size, &page); if (!addr) goto err_pool; for (i = 0; i < count; i++) pages[i] = page + i; *handle = __iommu_create_mapping(dev, pages, size); if (*handle == DMA_ERROR_CODE) goto err_mapping; return addr; err_mapping: __free_from_pool(addr, size); err_pool: kfree(pages); return NULL; } and then call it at the beginning of the arm_iommu_alloc_attrs(): if (gfp & GFP_ATOMIC) return __iommu_alloc_atomic(dev, size, handle); You should also add support for the allocation from atomic_pool to __iommu_get_pages() function to get dma_mmap() and dma_get_sgtable() working correctly. > @@ -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); > } Are you sure this one works? __iommu_get_pages() won't find pages array, because atomic allocations don't get their separate vm_struct area, so this check will be never reached. Maybe a __iommu_free_atomic() function would also make it safer and easier to understand. Best regards
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); }
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(-)