Re: [PATCH v1 5/6] media: videobuf2: Assert held reservation lock for dma-buf mmapping

[Tomasz Figa]

On Fri, Nov 11, 2022 at 5:15 AM Dmitry Osipenko
<dmitry.osipenko@xxxxxxxxxxxxx> wrote:
>
> When userspace mmaps dma-buf's fd, the dma-buf reservation lock must be
> held. Add locking sanity checks to the dma-buf mmaping callbacks to ensure
> that the locking assumptions won't regress in the future.
>
> Suggested-by: Daniel Vetter <daniel@xxxxxxxx>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
> ---
>  drivers/media/common/videobuf2/videobuf2-dma-contig.c | 3 +++
>  drivers/media/common/videobuf2/videobuf2-dma-sg.c     | 3 +++
>  drivers/media/common/videobuf2/videobuf2-vmalloc.c    | 3 +++
>  3 files changed, 9 insertions(+)
>

Acked-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>

Best regards,
Tomasz

> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index 555bd40fa472..7f45a62969f2 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -11,6 +11,7 @@
>   */
>
>  #include <linux/dma-buf.h>
> +#include <linux/dma-resv.h>
>  #include <linux/module.h>
>  #include <linux/refcount.h>
>  #include <linux/scatterlist.h>
> @@ -455,6 +456,8 @@ static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct iosys_map *map)
>  static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
>         struct vm_area_struct *vma)
>  {
> +       dma_resv_assert_held(dbuf->resv);
> +
>         return vb2_dc_mmap(dbuf->priv, vma);
>  }
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> index 36981a5b5c53..b7f39ee49ed8 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> @@ -10,6 +10,7 @@
>   * the Free Software Foundation.
>   */
>
> +#include <linux/dma-resv.h>
>  #include <linux/module.h>
>  #include <linux/mm.h>
>  #include <linux/refcount.h>
> @@ -495,6 +496,8 @@ static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf,
>  static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
>         struct vm_area_struct *vma)
>  {
> +       dma_resv_assert_held(dbuf->resv);
> +
>         return vb2_dma_sg_mmap(dbuf->priv, vma);
>  }
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> index 41db707e43a4..f9b665366365 100644
> --- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> +++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> @@ -10,6 +10,7 @@
>   * the Free Software Foundation.
>   */
>
> +#include <linux/dma-resv.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
>  #include <linux/mm.h>
> @@ -316,6 +317,8 @@ static int vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf,
>  static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
>         struct vm_area_struct *vma)
>  {
> +       dma_resv_assert_held(dbuf->resv);
> +
>         return vb2_vmalloc_mmap(dbuf->priv, vma);
>  }
>
> --
> 2.37.3
>