Re: [PATCH v3 5/6] media: uvcvideo: Use dma_alloc_noncontiguos API

[Christoph Hellwig]

On Thu, Nov 26, 2020 at 08:44:50PM +0900, Sergey Senozhatsky wrote:
> > +	uvc_urb->buffer = vmap(uvc_urb->pages,
> > +			       PAGE_ALIGN(stream->urb_size) >> PAGE_SHIFT,
> > +			       VM_DMA_COHERENT, PAGE_KERNEL);
> 
> This is not related to Ricardo's patch, just a side note:
> 
>   I think VM_DMA_COHERENT needs to be renamed. I found it a bit confusing
>   to see DMA_COHERENT mapping being dma_sync-ed. It turned out that the
>   flag has different meaning.

s/renamed/removed/.  This is a normal VM_MAP mapping as far as the
core vmalloc/vmap code is concerned.  VM_DMA_COHERENT is only for
internal use in the core DMA code.