Re: pci_alloc_consistent usage

[Christoph Hellwig <hch@infradead.org>]

On Tue, May 27, 2003 at 01:22:37PM +0200, Ralf Baechle wrote:
> [...]
> portably refer to any piece of memory.  If you have a cpu pointer
> (which may be validly DMA'd too) you may easily obtain the page
> and offset using something like this:
>                                                                               
>   
>         struct page *page = virt_to_page(ptr);
>         unsigned long offset = ((unsigned long)ptr & ~PAGE_MASK);
> [...]
> 
> While it's officially documented I still don't like it.

Hmm, I remembered that some ports used vmalloc-like allocators for
this and virt_to_page doesn't work for those..