From: Jan Kara <j...@suse.cz>

Convert vb2_dc_get_userptr() to use frame vector infrastructure. When we
are doing that there's no need to allocate page array and some code can
be simplified.

Tested-by: Marek Szyprowski <m.szyprow...@samsung.com>
Signed-off-by: Jan Kara <j...@suse.cz>
Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mche...@osg.samsung.com>

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c 
b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 369df95af5c7..2397ceb1dc6b 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -32,15 +32,13 @@ struct vb2_dc_buf {
        dma_addr_t                      dma_addr;
        enum dma_data_direction         dma_dir;
        struct sg_table                 *dma_sgt;
+       struct frame_vector             *vec;
 
        /* MMAP related */
        struct vb2_vmarea_handler       handler;
        atomic_t                        refcount;
        struct sg_table                 *sgt_base;
 
-       /* USERPTR related */
-       struct vm_area_struct           *vma;
-
        /* DMABUF related */
        struct dma_buf_attachment       *db_attach;
 };
@@ -49,24 +47,6 @@ struct vb2_dc_buf {
 /*        scatterlist table functions        */
 /*********************************************/
 
-
-static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
-       void (*cb)(struct page *pg))
-{
-       struct scatterlist *s;
-       unsigned int i;
-
-       for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
-               struct page *page = sg_page(s);
-               unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
-                       >> PAGE_SHIFT;
-               unsigned int j;
-
-               for (j = 0; j < n_pages; ++j, ++page)
-                       cb(page);
-       }
-}
-
 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
 {
        struct scatterlist *s;
@@ -429,92 +409,12 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, 
unsigned long flags)
 /*       callbacks for USERPTR buffers       */
 /*********************************************/
 
-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,
-       enum dma_data_direction dma_dir)
-{
-       if (vma_is_io(vma)) {
-               unsigned int i;
-
-               for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
-                       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;
-                       }
-                       pages[i] = pfn_to_page(pfn);
-               }
-       } else {
-               int n;
-
-               n = get_user_pages(current, current->mm, start & PAGE_MASK,
-                       n_pages, dma_dir == DMA_FROM_DEVICE, 1, pages, NULL);
-               /* negative error means that no page was pinned */
-               n = max(n, 0);
-               if (n != n_pages) {
-                       pr_err("got only %d of %d user pages\n", n, n_pages);
-                       while (n)
-                               put_page(pages[--n]);
-                       return -EFAULT;
-               }
-       }
-
-       return 0;
-}
-
-static void vb2_dc_put_dirty_page(struct page *page)
-{
-       set_page_dirty_lock(page);
-       put_page(page);
-}
-
 static void vb2_dc_put_userptr(void *buf_priv)
 {
        struct vb2_dc_buf *buf = buf_priv;
        struct sg_table *sgt = buf->dma_sgt;
+       int i;
+       struct page **pages;
 
        if (sgt) {
                DEFINE_DMA_ATTRS(attrs);
@@ -526,15 +426,15 @@ static void vb2_dc_put_userptr(void *buf_priv)
                 */
                dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
                                   buf->dma_dir, &attrs);
-               if (!vma_is_io(buf->vma))
-                       vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
-
+               pages = frame_vector_pages(buf->vec);
+               /* sgt should exist only if vector contains pages... */
+               BUG_ON(IS_ERR(pages));
+               for (i = 0; i < frame_vector_count(buf->vec); i++)
+                       set_page_dirty_lock(pages[i]);
                sg_free_table(sgt);
                kfree(sgt);
        }
-       down_read(&current->mm->mmap_sem);
-       vb2_put_vma(buf->vma);
-       up_read(&current->mm->mmap_sem);
+       vb2_destroy_framevec(buf->vec);
        kfree(buf);
 }
 
@@ -574,13 +474,10 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned 
long vaddr,
 {
        struct vb2_dc_conf *conf = alloc_ctx;
        struct vb2_dc_buf *buf;
-       unsigned long start;
-       unsigned long end;
+       struct frame_vector *vec;
        unsigned long offset;
-       struct page **pages;
-       int n_pages;
+       int n_pages, i;
        int ret = 0;
-       struct vm_area_struct *vma;
        struct sg_table *sgt;
        unsigned long contig_size;
        unsigned long dma_align = dma_get_cache_alignment();
@@ -606,75 +503,43 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned 
long vaddr,
        buf->dev = conf->dev;
        buf->dma_dir = dma_dir;
 
-       start = vaddr & PAGE_MASK;
        offset = vaddr & ~PAGE_MASK;
-       end = PAGE_ALIGN(vaddr + size);
-       n_pages = (end - start) >> PAGE_SHIFT;
-
-       pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
-       if (!pages) {
-               ret = -ENOMEM;
-               pr_err("failed to allocate pages table\n");
+       vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE);
+       if (IS_ERR(vec)) {
+               ret = PTR_ERR(vec);
                goto fail_buf;
        }
+       buf->vec = vec;
+       n_pages = frame_vector_count(vec);
+       ret = frame_vector_to_pages(vec);
+       if (ret < 0) {
+               unsigned long *nums = frame_vector_pfns(vec);
 
-       down_read(&current->mm->mmap_sem);
-       /* current->mm->mmap_sem is taken by videobuf2 core */
-       vma = find_vma(current->mm, vaddr);
-       if (!vma) {
-               pr_err("no vma for address %lu\n", vaddr);
-               ret = -EFAULT;
-               goto fail_pages;
+               /*
+                * Failed to convert to pages... Check the memory is physically
+                * contiguous and use direct mapping
+                */
+               for (i = 1; i < n_pages; i++)
+                       if (nums[i-1] + 1 != nums[i])
+                               goto fail_pfnvec;
+               buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
+               goto out;
        }
 
-       if (vma->vm_end < vaddr + size) {
-               pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
-               ret = -EFAULT;
-               goto fail_pages;
-       }
-
-       buf->vma = vb2_get_vma(vma);
-       if (!buf->vma) {
-               pr_err("failed to copy vma\n");
-               ret = -ENOMEM;
-               goto fail_pages;
-       }
-
-       /* extract page list from userspace mapping */
-       ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, dma_dir);
-       if (ret) {
-               unsigned long pfn;
-               if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
-                       up_read(&current->mm->mmap_sem);
-                       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;
-       }
-       up_read(&current->mm->mmap_sem);
-
        sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
        if (!sgt) {
                pr_err("failed to allocate sg table\n");
                ret = -ENOMEM;
-               goto fail_get_user_pages;
+               goto fail_pfnvec;
        }
 
-       ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
+       ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages,
                offset, size, GFP_KERNEL);
        if (ret) {
                pr_err("failed to initialize sg table\n");
                goto fail_sgt;
        }
 
-       /* pages are no longer needed */
-       kfree(pages);
-       pages = NULL;
-
        /*
         * No need to sync to the device, this will happen later when the
         * prepare() memop is called.
@@ -696,8 +561,9 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned 
long vaddr,
        }
 
        buf->dma_addr = sg_dma_address(sgt->sgl);
-       buf->size = size;
        buf->dma_sgt = sgt;
+out:
+       buf->size = size;
 
        return buf;
 
@@ -706,25 +572,13 @@ fail_map_sg:
                           buf->dma_dir, &attrs);
 
 fail_sgt_init:
-       if (!vma_is_io(buf->vma))
-               vb2_dc_sgt_foreach_page(sgt, put_page);
        sg_free_table(sgt);
 
 fail_sgt:
        kfree(sgt);
 
-fail_get_user_pages:
-       if (pages && !vma_is_io(buf->vma))
-               while (n_pages)
-                       put_page(pages[--n_pages]);
-
-       down_read(&current->mm->mmap_sem);
-fail_vma:
-       vb2_put_vma(buf->vma);
-
-fail_pages:
-       up_read(&current->mm->mmap_sem);
-       kfree(pages); /* kfree is NULL-proof */
+fail_pfnvec:
+       vb2_destroy_framevec(vec);
 
 fail_buf:
        kfree(buf);
-- 
2.4.2

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