Re: [PATCH] dma-buf: support 32bit DMA_BUF_SET_NAME ioctl

[Martin Liu <liumartin@google.com>]

On Tue, Jan 14, 2020 at 09:41:01PM +0800, Martin Liu wrote:

CC more MLs for winder review.

> This commit adds SET_NAME ioctl coversion to
> support 32 bit ioctl.
> 
> Signed-off-by: Martin Liu <liumartin@google.com>
> ---
>  drivers/dma-buf/dma-buf.c | 22 +++++++++++++++++++++-
>  1 file changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index ce41cd9b758a..a73048b34843 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -25,6 +25,7 @@
>  #include <linux/mm.h>
>  #include <linux/mount.h>
>  #include <linux/pseudo_fs.h>
> +#include <linux/compat.h>
>  
>  #include <uapi/linux/dma-buf.h>
>  #include <uapi/linux/magic.h>
> @@ -409,13 +410,32 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file)
>  	dma_resv_unlock(dmabuf->resv);
>  }
>  
> +#ifdef CONFIG_COMPAT
> +static long dma_buf_ioctl_compat(struct file *file, unsigned int cmd,
> +				 unsigned long arg)
> +{
> +	switch (_IOC_NR(cmd)) {
> +	case _IOC_NR(DMA_BUF_SET_NAME):
> +		/* Fix up pointer size*/
> +		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
> +			cmd &= ~IOCSIZE_MASK;
> +			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
> +		}
> +		break;
> +	}
> +	return dma_buf_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
> +}
> +#endif
> +
>  static const struct file_operations dma_buf_fops = {
>  	.release	= dma_buf_release,
>  	.mmap		= dma_buf_mmap_internal,
>  	.llseek		= dma_buf_llseek,
>  	.poll		= dma_buf_poll,
>  	.unlocked_ioctl	= dma_buf_ioctl,
> -	.compat_ioctl	= compat_ptr_ioctl,
> +#ifdef CONFIG_COMPAT
> +	.compat_ioctl	= dma_buf_ioctl_compat,
> +#endif
>  	.show_fdinfo	= dma_buf_show_fdinfo,
>  };
>  
> -- 
> 2.25.0.rc1.283.g88dfdc4193-goog
>