Re: [PATCH] USB: usbfs: fix mmap dma mismatch

[Greg Kroah-Hartman]

On Thu, May 14, 2020 at 01:58:29PM +0200, Christoph Hellwig wrote:
> On Thu, May 14, 2020 at 01:27:11PM +0200, Greg Kroah-Hartman wrote:
> > +	if (hcd->localmem_pool || !hcd_uses_dma(hcd)) {
> > +		if (remap_pfn_range(vma, vma->vm_start,
> > +				    virt_to_phys(usbm->mem) >> PAGE_SHIFT,
> > +				    size, vma->vm_page_prot) < 0) {
> > +			dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
> > +			return -EAGAIN;
> > +		}
> > +	} else {
> > +		if (dma_mmap_coherent(hcd->self.sysdev, vma, mem, dma_handle,
> > +				      size)) {
> > +			dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
> > +			return -EAGAIN;
> > +		}
> 
> What about a goto label to share the error handling path?

I thought about that, but that's a bit messier than the duplicated lines
here :)

> Otherwise looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>

thanks for the review, and the help with this.

greg k-h