[PATCH 6/7] dma-iommu: implement ->alloc_noncontiguous

[Christoph Hellwig]

Implement support for allocating a non-contiguous DMA region.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/iommu/dma-iommu.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 85cb004d7a44c6..4e0b170d38d57a 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -718,6 +718,7 @@ 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:
@@ -755,6 +756,36 @@ static void *iommu_dma_alloc_remap(struct device *dev, 
size_t size,
        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)
+{
+       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, 0);
+       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)
 {
@@ -1270,6 +1301,10 @@ 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,
-- 
2.29.2

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