Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[cascardo/linux.git] / drivers / media / v4l2-core / videobuf2-dma-contig.c

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index fd56f25..646f08f 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -423,6 +423,39 @@ static inline int vma_is_io(struct vm_area_struct *vma)
        return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 }
 
+static int vb2_dc_get_user_pfn(unsigned long start, int n_pages,
+       struct vm_area_struct *vma, unsigned long *res)
+{
+       unsigned long pfn, start_pfn, prev_pfn;
+       unsigned int i;
+       int ret;
+
+       if (!vma_is_io(vma))
+               return -EFAULT;
+
+       ret = follow_pfn(vma, start, &pfn);
+       if (ret)
+               return ret;
+
+       start_pfn = pfn;
+       start += PAGE_SIZE;
+
+       for (i = 1; i < n_pages; ++i, start += PAGE_SIZE) {
+               prev_pfn = pfn;
+               ret = follow_pfn(vma, start, &pfn);
+
+               if (ret) {
+                       pr_err("no page for address %lu\n", start);
+                       return ret;
+               }
+               if (pfn != prev_pfn + 1)
+                       return -EINVAL;
+       }
+
+       *res = start_pfn;
+       return 0;
+}
+
 static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
        int n_pages, struct vm_area_struct *vma, int write)
 {
@@ -433,6 +466,9 @@ static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
                        unsigned long pfn;
                        int ret = follow_pfn(vma, start, &pfn);
 
+                       if (!pfn_valid(pfn))
+                               return -EINVAL;
+
                        if (ret) {
                                pr_err("no page for address %lu\n", start);
                                return ret;
@@ -468,16 +504,49 @@ static void vb2_dc_put_userptr(void *buf_priv)
        struct vb2_dc_buf *buf = buf_priv;
        struct sg_table *sgt = buf->dma_sgt;
 
-       dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
-       if (!vma_is_io(buf->vma))
-               vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
+       if (sgt) {
+               dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
+               if (!vma_is_io(buf->vma))
+                       vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
 
-       sg_free_table(sgt);
-       kfree(sgt);
+               sg_free_table(sgt);
+               kfree(sgt);
+       }
        vb2_put_vma(buf->vma);
        kfree(buf);
 }
 
+/*
+ * For some kind of reserved memory there might be no struct page available,
+ * so all that can be done to support such 'pages' is to try to convert
+ * pfn to dma address or at the last resort just assume that
+ * dma address == physical address (like it has been assumed in earlier version
+ * of videobuf2-dma-contig
+ */
+
+#ifdef __arch_pfn_to_dma
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+       return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
+}
+#elif defined(__pfn_to_bus)
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+       return (dma_addr_t)__pfn_to_bus(pfn);
+}
+#elif defined(__pfn_to_phys)
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+       return (dma_addr_t)__pfn_to_phys(pfn);
+}
+#else
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+       /* really, we cannot do anything better at this point */
+       return (dma_addr_t)(pfn) << PAGE_SHIFT;
+}
+#endif
+
 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
        unsigned long size, int write)
 {
@@ -548,6 +617,14 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
        /* extract page list from userspace mapping */
        ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
        if (ret) {
+               unsigned long pfn;
+               if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
+                       buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn);
+                       buf->size = size;
+                       kfree(pages);
+                       return buf;
+               }
+
                pr_err("failed to get user pages\n");
                goto fail_vma;
        }