Re: [PATCH] staging: android: ion: refactory ion_alloc for kernel driver use

Greg Kroah-Hartman
2019-03-29T16:02:02Z

On Sat, Mar 30, 2019 at 02:40:16AM +0800, Zeng Tao wrote:
> There are two reasons for this patch:
> 1. There are some potential requirements for ion_alloc in kernel space,
> some media drivers need to allocate media buffers from ion instead of
> buddy or dma framework, this is more convient and clean very for media
> drivers. And In that case, ion is the only media buffer provider, it's
> more easier to maintain.
> 2. Fd is only needed by user processes, not the kernel space, so dma_buf
> should be returned instead of fd for kernel space, and dma_buf_fd should
> be called only for userspace api.
>
> Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com>
> ---
> drivers/staging/android/ion/ion.c | 32 +++++++++++++++++---------------
> 1 file changed, 17 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 92c2914..e93fb49 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -387,13 +387,13 @@ static const struct dma_buf_ops dma_buf_ops = {
> .unmap = ion_dma_buf_kunmap,
> };
>
> -static int ion_alloc(size_t len, unsigned int heap_id_mask, unsigned int flags)
> +struct dma_buf *ion_alloc(size_t len, unsigned int heap_id_mask,
> + unsigned int flags)
> {
> struct ion_device *dev = internal_dev;
> struct ion_buffer *buffer = NULL;
> struct ion_heap *heap;
> DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> - int fd;
> struct dma_buf *dmabuf;
>
> pr_debug("%s: len %zu heap_id_mask %u flags %x\n", __func__,
> @@ -407,7 +407,7 @@ static int ion_alloc(size_t len, unsigned int heap_id_mask, unsigned int flags)
> len = PAGE_ALIGN(len);
>
> if (!len)
> - return -EINVAL;
> + return ERR_PTR(-EINVAL);
>
> down_read(&dev->lock);
> plist_for_each_entry(heap, &dev->heaps, node) {
> @@ -421,10 +421,10 @@ static int ion_alloc(size_t len, unsigned int heap_id_mask, unsigned int flags)
> up_read(&dev->lock);
>
> if (!buffer)
> - return -ENODEV;
> + return ERR_PTR(-ENODEV);
>
> if (IS_ERR(buffer))
> - return PTR_ERR(buffer);
> + return ERR_PTR(PTR_ERR(buffer));
>
> exp_info.ops = &dma_buf_ops;
> exp_info.size = buffer->size;
> @@ -432,17 +432,12 @@ static int ion_alloc(size_t len, unsigned int heap_id_mask, unsigned int flags)
> exp_info.priv = buffer;
>
> dmabuf = dma_buf_export(&exp_info);
> - if (IS_ERR(dmabuf)) {
> + if (IS_ERR(dmabuf))
> _ion_buffer_destroy(buffer);
> - return PTR_ERR(dmabuf);
> - }
>
> - fd = dma_buf_fd(dmabuf, O_CLOEXEC);
> - if (fd < 0)
> - dma_buf_put(dmabuf);
> -
> - return fd;
> + return dmabuf;
> }
> +EXPORT_SYMBOL(ion_alloc);

If you are going to do this (and personally I'm with Laura in that I
don't think you need it) this should be EXPORT_SYMBOL_GPL() please.

thanks,

greg k-h