On Fri, 30 Aug 2013, Konrad Rzeszutek Wilk wrote: > On Thu, Aug 29, 2013 at 07:32:33PM +0100, Stefano Stabellini wrote: > > Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or > > free coherent pages. > > > > We need to be careful handling the pointer returned by > > xen_alloc_coherent_pages, because on ARM the pointer is not equal to > > phys_to_virt(*dma_handle). In fact virt_to_phys on the returned pointer > > doesn't return a valid physical address. > > Why is it called 'virt_to_phys'? What does it return then?
virt_to_phys only works for kernel direct mapped RAM memory. In this case the virtual address could be an ioremap address, therefore passing it to virt_to_phys would give you another physical address that doesn't correspond to it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
