From 863981e96738983919de841ec669e157e6bdaeb0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Sun, 11 Sep 2016 04:34:46 -0300 Subject: Linux-libre 4.7.1-gnu --- drivers/iommu/dma-iommu.c | 146 ++++++++++++++++++++++++++++++++-------------- 1 file changed, 101 insertions(+), 45 deletions(-) (limited to 'drivers/iommu/dma-iommu.c') diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 58f2fe687..ea5a9ebf0 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -94,7 +94,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size return -ENODEV; /* Use the smallest supported page size for IOVA granularity */ - order = __ffs(domain->ops->pgsize_bitmap); + order = __ffs(domain->pgsize_bitmap); base_pfn = max_t(unsigned long, 1, base >> order); end_pfn = (base + size - 1) >> order; @@ -190,11 +190,15 @@ static void __iommu_dma_free_pages(struct page **pages, int count) kvfree(pages); } -static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp) +static struct page **__iommu_dma_alloc_pages(unsigned int count, + unsigned long order_mask, gfp_t gfp) { struct page **pages; unsigned int i = 0, array_size = count * sizeof(*pages); - unsigned int order = MAX_ORDER; + + order_mask &= (2U << MAX_ORDER) - 1; + if (!order_mask) + return NULL; if (array_size <= PAGE_SIZE) pages = kzalloc(array_size, GFP_KERNEL); @@ -208,36 +212,38 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp) while (count) { struct page *page = NULL; - int j; + unsigned int order_size; /* * Higher-order allocations are a convenience rather * than a necessity, hence using __GFP_NORETRY until - * falling back to single-page allocations. + * falling back to minimum-order allocations. */ - for (order = min_t(unsigned int, order, __fls(count)); - order > 0; order--) { - page = alloc_pages(gfp | __GFP_NORETRY, order); + for (order_mask &= (2U << __fls(count)) - 1; + order_mask; order_mask &= ~order_size) { + unsigned int order = __fls(order_mask); + + order_size = 1U << order; + page = alloc_pages((order_mask - order_size) ? + gfp | __GFP_NORETRY : gfp, order); if (!page) continue; - if (PageCompound(page)) { - if (!split_huge_page(page)) - break; - __free_pages(page, order); - } else { + if (!order) + break; + if (!PageCompound(page)) { split_page(page, order); break; + } else if (!split_huge_page(page)) { + break; } + __free_pages(page, order); } - if (!page) - page = alloc_page(gfp); if (!page) { __iommu_dma_free_pages(pages, i); return NULL; } - j = 1 << order; - count -= j; - while (j--) + count -= order_size; + while (order_size--) pages[i++] = page++; } return pages; @@ -267,6 +273,7 @@ void iommu_dma_free(struct device *dev, struct page **pages, size_t size, * attached to an iommu_dma_domain * @size: Size of buffer in bytes * @gfp: Allocation flags + * @attrs: DMA attributes for this allocation * @prot: IOMMU mapping flags * @handle: Out argument for allocated DMA handle * @flush_page: Arch callback which must ensure PAGE_SIZE bytes from the @@ -278,8 +285,8 @@ void iommu_dma_free(struct device *dev, struct page **pages, size_t size, * Return: Array of struct page pointers describing the buffer, * or NULL on failure. */ -struct page **iommu_dma_alloc(struct device *dev, size_t size, - gfp_t gfp, int prot, dma_addr_t *handle, +struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, + struct dma_attrs *attrs, int prot, dma_addr_t *handle, void (*flush_page)(struct device *, const void *, phys_addr_t)) { struct iommu_domain *domain = iommu_get_domain_for_dev(dev); @@ -288,11 +295,22 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, struct page **pages; struct sg_table sgt; dma_addr_t dma_addr; - unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; + unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap; *handle = DMA_ERROR_CODE; - pages = __iommu_dma_alloc_pages(count, gfp); + min_size = alloc_sizes & -alloc_sizes; + if (min_size < PAGE_SIZE) { + min_size = PAGE_SIZE; + alloc_sizes |= PAGE_SIZE; + } else { + size = ALIGN(size, min_size); + } + if (dma_get_attr(DMA_ATTR_ALLOC_SINGLE_PAGES, attrs)) + alloc_sizes = min_size; + + count = PAGE_ALIGN(size) >> PAGE_SHIFT; + pages = __iommu_dma_alloc_pages(count, alloc_sizes >> PAGE_SHIFT, gfp); if (!pages) return NULL; @@ -389,26 +407,58 @@ void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size, /* * Prepare a successfully-mapped scatterlist to give back to the caller. - * Handling IOVA concatenation can come later, if needed + * + * At this point the segments are already laid out by iommu_dma_map_sg() to + * avoid individually crossing any boundaries, so we merely need to check a + * segment's start address to avoid concatenating across one. */ static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents, dma_addr_t dma_addr) { - struct scatterlist *s; - int i; + struct scatterlist *s, *cur = sg; + unsigned long seg_mask = dma_get_seg_boundary(dev); + unsigned int cur_len = 0, max_len = dma_get_max_seg_size(dev); + int i, count = 0; for_each_sg(sg, s, nents, i) { - /* Un-swizzling the fields here, hence the naming mismatch */ - unsigned int s_offset = sg_dma_address(s); + /* Restore this segment's original unaligned fields first */ + unsigned int s_iova_off = sg_dma_address(s); unsigned int s_length = sg_dma_len(s); - unsigned int s_dma_len = s->length; + unsigned int s_iova_len = s->length; - s->offset += s_offset; + s->offset += s_iova_off; s->length = s_length; - sg_dma_address(s) = dma_addr + s_offset; - dma_addr += s_dma_len; + sg_dma_address(s) = DMA_ERROR_CODE; + sg_dma_len(s) = 0; + + /* + * Now fill in the real DMA data. If... + * - there is a valid output segment to append to + * - and this segment starts on an IOVA page boundary + * - but doesn't fall at a segment boundary + * - and wouldn't make the resulting output segment too long + */ + if (cur_len && !s_iova_off && (dma_addr & seg_mask) && + (cur_len + s_length <= max_len)) { + /* ...then concatenate it with the previous one */ + cur_len += s_length; + } else { + /* Otherwise start the next output segment */ + if (i > 0) + cur = sg_next(cur); + cur_len = s_length; + count++; + + sg_dma_address(cur) = dma_addr + s_iova_off; + } + + sg_dma_len(cur) = cur_len; + dma_addr += s_iova_len; + + if (s_length + s_iova_off < s_iova_len) + cur_len = 0; } - return i; + return count; } /* @@ -446,34 +496,40 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, struct scatterlist *s, *prev = NULL; dma_addr_t dma_addr; size_t iova_len = 0; + unsigned long mask = dma_get_seg_boundary(dev); int i; /* * Work out how much IOVA space we need, and align the segments to * IOVA granules for the IOMMU driver to handle. With some clever * trickery we can modify the list in-place, but reversibly, by - * hiding the original data in the as-yet-unused DMA fields. + * stashing the unaligned parts in the as-yet-unused DMA fields. */ for_each_sg(sg, s, nents, i) { - size_t s_offset = iova_offset(iovad, s->offset); + size_t s_iova_off = iova_offset(iovad, s->offset); size_t s_length = s->length; + size_t pad_len = (mask - iova_len + 1) & mask; - sg_dma_address(s) = s_offset; + sg_dma_address(s) = s_iova_off; sg_dma_len(s) = s_length; - s->offset -= s_offset; - s_length = iova_align(iovad, s_length + s_offset); + s->offset -= s_iova_off; + s_length = iova_align(iovad, s_length + s_iova_off); s->length = s_length; /* - * The simple way to avoid the rare case of a segment - * crossing the boundary mask is to pad the previous one - * to end at a naturally-aligned IOVA for this one's size, - * at the cost of potentially over-allocating a little. + * Due to the alignment of our single IOVA allocation, we can + * depend on these assumptions about the segment boundary mask: + * - If mask size >= IOVA size, then the IOVA range cannot + * possibly fall across a boundary, so we don't care. + * - If mask size < IOVA size, then the IOVA range must start + * exactly on a boundary, therefore we can lay things out + * based purely on segment lengths without needing to know + * the actual addresses beforehand. + * - The mask must be a power of 2, so pad_len == 0 if + * iova_len == 0, thus we cannot dereference prev the first + * time through here (i.e. before it has a meaningful value). */ - if (prev) { - size_t pad_len = roundup_pow_of_two(s_length); - - pad_len = (pad_len - iova_len) & (pad_len - 1); + if (pad_len && pad_len < s_length - 1) { prev->length += pad_len; iova_len += pad_len; } -- cgit v1.2.3-54-g00ecf