This is patch to remove vb2_dc_kaddr_to_pages() function with dma_get_sgtable() in the patch set posted by Tomasz. It was observed that the former function fails to get the pages, as follow_pfn() can fail for remapped kernel va provided by the dma-mapping sub-system.
As Tomasz mentioned, the later call was temporary patch until dma-mapping author finalizes the implementation of dma_get_sgtable(). One can use this patch to use this vb2 patch-set for his/her work in the meantime. Signed-off-by: Subash Patel <subash.ramaswamy at linaro.org> --- drivers/media/video/videobuf2-dma-contig.c | 53 ++------------------------- 1 files changed, 4 insertions(+), 49 deletions(-) diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index e8da7f1..1b9023a 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -143,32 +143,11 @@ static void vb2_dc_put(void *buf_priv) kfree(buf); } -static int vb2_dc_kaddr_to_pages(unsigned long kaddr, - struct page **pages, unsigned int n_pages) -{ - unsigned int i; - unsigned long pfn; - struct vm_area_struct vma = { - .vm_flags = VM_IO | VM_PFNMAP, - .vm_mm = current->mm, - }; - - for (i = 0; i < n_pages; ++i, kaddr += PAGE_SIZE) { - if (follow_pfn(&vma, kaddr, &pfn)) - break; - pages[i] = pfn_to_page(pfn); - } - - return i; -} - static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size) { struct device *dev = alloc_ctx; struct vb2_dc_buf *buf; int ret = -ENOMEM; - int n_pages; - struct page **pages = NULL; buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) @@ -183,35 +162,14 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size) WARN_ON((unsigned long)buf->vaddr & ~PAGE_MASK); WARN_ON(buf->dma_addr & ~PAGE_MASK); - n_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; + ret = dma_get_sgtable(dev, &buf->sgt_base, buf->vaddr, + buf->dma_addr, size, NULL); - pages = kmalloc(n_pages * sizeof pages[0], GFP_KERNEL); - if (!pages) { - dev_err(dev, "failed to alloc page table\n"); - goto fail_dma; - } - - ret = vb2_dc_kaddr_to_pages((unsigned long)buf->vaddr, pages, n_pages); if (ret < 0) { - dev_err(dev, "failed to get buffer pages from DMA API\n"); - goto fail_pages; - } - if (ret != n_pages) { - ret = -EFAULT; - dev_err(dev, "failed to get all pages from DMA API\n"); - goto fail_pages; - } - - ret = sg_alloc_table_from_pages(&buf->sgt_base, - pages, n_pages, 0, size, GFP_KERNEL); - if (ret) { - dev_err(dev, "failed to prepare sg table\n"); - goto fail_pages; + dev_err(dev, "failed to get the SGT for the allocated pages\n"); + goto fail_dma; } - /* pages are no longer needed */ - kfree(pages); - buf->dev = dev; buf->size = size; @@ -223,9 +181,6 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size) return buf; -fail_pages: - kfree(pages); - fail_dma: dma_free_coherent(dev, size, buf->vaddr, buf->dma_addr); -- 1.7.5.4 --------------080106050707070506020705--