Adding Alan Cox, as he pushed this driver upstream...

On Sun, Aug 31, 2014 at 09:46:22PM +0530, Sudip Mukherjee wrote:
> fixed sparse warning of incorrect type in argument 1 and incorrect type in 
> argument 2
> it was directly dereferencing a __iomem pointer , which will work in x86 but 
> will fail in other architectures.

Please wrap your changelog comments at 72 columns...

> Signed-off-by: Sudip Mukherjee <su...@vectorindia.org>
> ---
> 
> hi,
> can you please reveiew the patch and check if the approach is correct. If it 
> is correct then I can send another patch to correct the other similar 
> warnings present in this file. 

I don't think this is correct, because:

> 
>  drivers/staging/goldfish/goldfish_audio.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/goldfish/goldfish_audio.c 
> b/drivers/staging/goldfish/goldfish_audio.c
> index c89d0b8..f9a13e7 100644
> --- a/drivers/staging/goldfish/goldfish_audio.c
> +++ b/drivers/staging/goldfish/goldfish_audio.c
> @@ -118,6 +118,7 @@ static ssize_t goldfish_audio_read(struct file *fp, char 
> __user *buf,
>       struct goldfish_audio *data = fp->private_data;
>       int length;
>       int result = 0;
> +     void *buffer;
>  
>       if (!data->read_supported)
>               return -ENODEV;
> @@ -133,9 +134,15 @@ static ssize_t goldfish_audio_read(struct file *fp, char 
> __user *buf,
>                                               AUDIO_READ_BUFFER_AVAILABLE);
>  
>               /* copy data to user space */
> -             if (copy_to_user(buf, data->read_buffer, length))
> +             buffer = kzalloc(length, GFP_KERNEL);
> +             if (buffer == NULL)
> +                     return -ENOMEM;
> +             memcpy_fromio(buffer, data->read_buffer, length);
> +             if (copy_to_user((void __user *)buf, buffer, length)) {
> +                     kfree(buffer);
>                       return -EFAULT;
> -
> +             }
> +             kfree(buffer);

The goldfish platform is an "emulator" so iomem is (or should be?) the
same as "normal" memory here.  So I think this is a false-positive.

But I could be totally wrong here, Alan?

thanks,

greg k-h
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