From 8230ce9a4e206fa1be17d66245f87cae2935d7d2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 28 Jan 2021 14:44:15 +0100 Subject: dma-iommu: refactor iommu_dma_alloc_remap Split out a new helper that only allocates a sg_table worth of memory without mapping it into contiguous kernel address space. Signed-off-by: Christoph Hellwig Reviewed-by: Tomasz Figa Tested-by: Ricardo Ribalda --- drivers/iommu/dma-iommu.c | 67 +++++++++++++++++++++++++---------------------- 1 file changed, 35 insertions(+), 32 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index af765c813cc8..ec1abad156db 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -650,23 +650,12 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev, return pages; } -/** - * iommu_dma_alloc_remap - Allocate and map a buffer contiguous in IOVA space - * @dev: Device to allocate memory for. Must be a real device - * attached to an iommu_dma_domain - * @size: Size of buffer in bytes - * @dma_handle: Out argument for allocated DMA handle - * @gfp: Allocation flags - * @prot: pgprot_t to use for the remapped mapping - * @attrs: DMA attributes for this allocation - * - * If @size is less than PAGE_SIZE, then a full CPU page will be allocated, +/* + * If size is less than PAGE_SIZE, then a full CPU page will be allocated, * but an IOMMU which supports smaller pages might not map the whole thing. - * - * Return: Mapped virtual address, or NULL on failure. */ -static void *iommu_dma_alloc_remap(struct device *dev, size_t size, - dma_addr_t *dma_handle, gfp_t gfp, pgprot_t prot, +static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev, + size_t size, struct sg_table *sgt, gfp_t gfp, pgprot_t prot, unsigned long attrs) { struct iommu_domain *domain = iommu_get_dma_domain(dev); @@ -676,11 +665,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size, int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap; struct page **pages; - struct sg_table sgt; dma_addr_t iova; - void *vaddr; - - *dma_handle = DMA_MAPPING_ERROR; if (static_branch_unlikely(&iommu_deferred_attach_enabled) && iommu_deferred_attach(dev, domain)) @@ -707,38 +692,56 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size, if (!iova) goto out_free_pages; - if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL)) + if (sg_alloc_table_from_pages(sgt, pages, count, 0, size, GFP_KERNEL)) goto out_free_iova; if (!(ioprot & IOMMU_CACHE)) { struct scatterlist *sg; int i; - for_each_sg(sgt.sgl, sg, sgt.orig_nents, i) + for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) arch_dma_prep_coherent(sg_page(sg), sg->length); } - if (iommu_map_sg_atomic(domain, iova, sgt.sgl, sgt.orig_nents, ioprot) + if (iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot) < size) goto out_free_sg; + sgt->sgl->dma_address = iova; + return pages; + +out_free_sg: + sg_free_table(sgt); +out_free_iova: + iommu_dma_free_iova(cookie, iova, size, NULL); +out_free_pages: + __iommu_dma_free_pages(pages, count); + return NULL; +} + +static void *iommu_dma_alloc_remap(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, pgprot_t prot, + unsigned long attrs) +{ + struct page **pages; + struct sg_table sgt; + void *vaddr; + + pages = __iommu_dma_alloc_noncontiguous(dev, size, &sgt, gfp, prot, + attrs); + if (!pages) + return NULL; + *dma_handle = sgt.sgl->dma_address; + sg_free_table(&sgt); vaddr = dma_common_pages_remap(pages, size, prot, __builtin_return_address(0)); if (!vaddr) goto out_unmap; - - *dma_handle = iova; - sg_free_table(&sgt); return vaddr; out_unmap: - __iommu_dma_unmap(dev, iova, size); -out_free_sg: - sg_free_table(&sgt); -out_free_iova: - iommu_dma_free_iova(cookie, iova, size, NULL); -out_free_pages: - __iommu_dma_free_pages(pages, count); + __iommu_dma_unmap(dev, *dma_handle, size); + __iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT); return NULL; } -- cgit v1.2.3 From e817ee5f2f95ca58a3b961ae4acfd3885e830b9c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 28 Jan 2021 14:47:29 +0100 Subject: dma-iommu: implement ->alloc_noncontiguous Implement support for allocating a non-contiguous DMA region. Signed-off-by: Christoph Hellwig Reviewed-by: Tomasz Figa Tested-by: Ricardo Ribalda --- drivers/iommu/dma-iommu.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'drivers/iommu') diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index ec1abad156db..1946422e4ac7 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -708,6 +708,7 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev, goto out_free_sg; sgt->sgl->dma_address = iova; + sgt->sgl->dma_length = size; return pages; out_free_sg: @@ -745,6 +746,37 @@ out_unmap: return NULL; } +#ifdef CONFIG_DMA_REMAP +static struct sg_table *iommu_dma_alloc_noncontiguous(struct device *dev, + size_t size, enum dma_data_direction dir, gfp_t gfp, + unsigned long attrs) +{ + struct dma_sgt_handle *sh; + + sh = kmalloc(sizeof(*sh), gfp); + if (!sh) + return NULL; + + sh->pages = __iommu_dma_alloc_noncontiguous(dev, size, &sh->sgt, gfp, + PAGE_KERNEL, attrs); + if (!sh->pages) { + kfree(sh); + return NULL; + } + return &sh->sgt; +} + +static void iommu_dma_free_noncontiguous(struct device *dev, size_t size, + struct sg_table *sgt, enum dma_data_direction dir) +{ + struct dma_sgt_handle *sh = sgt_handle(sgt); + + __iommu_dma_unmap(dev, sgt->sgl->dma_address, size); + __iommu_dma_free_pages(sh->pages, PAGE_ALIGN(size) >> PAGE_SHIFT); + sg_free_table(&sh->sgt); +} +#endif /* CONFIG_DMA_REMAP */ + static void iommu_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction dir) { @@ -1261,6 +1293,10 @@ static const struct dma_map_ops iommu_dma_ops = { .free = iommu_dma_free, .alloc_pages = dma_common_alloc_pages, .free_pages = dma_common_free_pages, +#ifdef CONFIG_DMA_REMAP + .alloc_noncontiguous = iommu_dma_alloc_noncontiguous, + .free_noncontiguous = iommu_dma_free_noncontiguous, +#endif .mmap = iommu_dma_mmap, .get_sgtable = iommu_dma_get_sgtable, .map_page = iommu_dma_map_page, -- cgit v1.2.3