Hi,
On Wednesday 10 August 2011 10:23:37 Marek Szyprowski wrote:
> From: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
>
> Scatter-gather lib provides a helper functions to allocate scatter list,
> so there is no need to use vmalloc for it. sg_alloc_table() splits
> allocation into page size chunks and links them together into a chain.
Last time I check ARM platforms didn't support SG list chaining. Has that been
fixed ?
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> CC: Pawel Osciak <pawel@xxxxxxxxxx>
> ---
> drivers/media/video/videobuf2-dma-sg.c | 54
> +++++++++++++++++++------------ 1 files changed, 33 insertions(+), 21
> deletions(-)
>
> diff --git a/drivers/media/video/videobuf2-dma-sg.c
> b/drivers/media/video/videobuf2-dma-sg.c index 065f468..e1158f9 100644
> --- a/drivers/media/video/videobuf2-dma-sg.c
> +++ b/drivers/media/video/videobuf2-dma-sg.c
> @@ -36,6 +36,8 @@ static void vb2_dma_sg_put(void *buf_priv);
> static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size)
> {
> struct vb2_dma_sg_buf *buf;
> + struct sg_table sgt;
> + struct scatterlist *sl;
> int i;
>
> buf = kzalloc(sizeof *buf, GFP_KERNEL);
> @@ -48,23 +50,21 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned
> long size) buf->sg_desc.size = size;
> buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
>
> - buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages *
> - sizeof(*buf->sg_desc.sglist));
> - if (!buf->sg_desc.sglist)
> + if (sg_alloc_table(&sgt, buf->sg_desc.num_pages, GFP_KERNEL))
> goto fail_sglist_alloc;
> - sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
> + buf->sg_desc.sglist = sgt.sgl;
>
> buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
> GFP_KERNEL);
> if (!buf->pages)
> goto fail_pages_array_alloc;
>
> - for (i = 0; i < buf->sg_desc.num_pages; ++i) {
> - buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
> + for_each_sg(buf->sg_desc.sglist, sl, buf->sg_desc.num_pages, i) {
> + buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO |
> + __GFP_NOWARN);
> if (NULL == buf->pages[i])
> goto fail_pages_alloc;
> - sg_set_page(&buf->sg_desc.sglist[i],
> - buf->pages[i], PAGE_SIZE, 0);
> + sg_set_page(sl, buf->pages[i], PAGE_SIZE, 0);
> }
>
> buf->handler.refcount = &buf->refcount;
> @@ -89,7 +89,7 @@ fail_pages_alloc:
> kfree(buf->pages);
>
> fail_pages_array_alloc:
> - vfree(buf->sg_desc.sglist);
> + sg_free_table(&sgt);
>
> fail_sglist_alloc:
> kfree(buf);
> @@ -99,6 +99,7 @@ fail_sglist_alloc:
> static void vb2_dma_sg_put(void *buf_priv)
> {
> struct vb2_dma_sg_buf *buf = buf_priv;
> + struct sg_table sgt;
> int i = buf->sg_desc.num_pages;
>
> if (atomic_dec_and_test(&buf->refcount)) {
> @@ -106,7 +107,9 @@ static void vb2_dma_sg_put(void *buf_priv)
> buf->sg_desc.num_pages);
> if (buf->vaddr)
> vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
> - vfree(buf->sg_desc.sglist);
> + sgt.sgl = buf->sg_desc.sglist;
> + sgt.orig_nents = sgt.nents = i;
> + sg_free_table(&sgt);
> while (--i >= 0)
> __free_page(buf->pages[i]);
> kfree(buf->pages);
> @@ -118,6 +121,8 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx,
> unsigned long vaddr, unsigned long size, int write)
> {
> struct vb2_dma_sg_buf *buf;
> + struct sg_table sgt;
> + struct scatterlist *sl;
> unsigned long first, last;
> int num_pages_from_user, i;
>
> @@ -134,12 +139,9 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx,
> unsigned long vaddr, last = ((vaddr + size - 1) & PAGE_MASK) >>
> PAGE_SHIFT;
> buf->sg_desc.num_pages = last - first + 1;
>
> - buf->sg_desc.sglist = vzalloc(
> - buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
> - if (!buf->sg_desc.sglist)
> + if (sg_alloc_table(&sgt, buf->sg_desc.num_pages, GFP_KERNEL))
> goto userptr_fail_sglist_alloc;
> -
> - sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
> + buf->sg_desc.sglist = sgt.sgl;
>
> buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
> GFP_KERNEL);
> @@ -158,12 +160,12 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx,
> unsigned long vaddr, if (num_pages_from_user != buf->sg_desc.num_pages)
> goto userptr_fail_get_user_pages;
>
> - sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0],
> - PAGE_SIZE - buf->offset, buf->offset);
> + sl = buf->sg_desc.sglist;
> + sg_set_page(sl, buf->pages[0], PAGE_SIZE - buf->offset, buf->offset);
> size -= PAGE_SIZE - buf->offset;
> for (i = 1; i < buf->sg_desc.num_pages; ++i) {
> - sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i],
> - min_t(size_t, PAGE_SIZE, size), 0);
> + sl = sg_next(sl);
> + sg_set_page(sl, buf->pages[i], min_t(size_t, PAGE_SIZE, size), 0);
> size -= min_t(size_t, PAGE_SIZE, size);
> }
> return buf;
> @@ -176,7 +178,7 @@ userptr_fail_get_user_pages:
> kfree(buf->pages);
>
> userptr_fail_pages_array_alloc:
> - vfree(buf->sg_desc.sglist);
> + sg_free_table(&sgt);
>
> userptr_fail_sglist_alloc:
> kfree(buf);
> @@ -190,6 +192,8 @@ userptr_fail_sglist_alloc:
> static void vb2_dma_sg_put_userptr(void *buf_priv)
> {
> struct vb2_dma_sg_buf *buf = buf_priv;
> + struct sg_table sgt;
> +
> int i = buf->sg_desc.num_pages;
>
> printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n",
> @@ -201,7 +205,9 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
> set_page_dirty_lock(buf->pages[i]);
> put_page(buf->pages[i]);
> }
> - vfree(buf->sg_desc.sglist);
> + sgt.sgl = buf->sg_desc.sglist;
> + sgt.orig_nents = sgt.nents = buf->sg_desc.num_pages;
> + sg_free_table(&sgt);
> kfree(buf->pages);
> kfree(buf);
> }
> @@ -218,6 +224,12 @@ static void *vb2_dma_sg_vaddr(void *buf_priv)
> -1,
> PAGE_KERNEL);
>
> + if (!buf->vaddr) {
> + printk(KERN_ERR "Cannot map buffer memory "
> + "into kernel address space\n");
> + return NULL;
> + }
> +
> /* add offset in case userptr is not page-aligned */
> return buf->vaddr + buf->offset;
> }
--
Regards,
Laurent Pinchart
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