On Thu, Oct 18 2007, Arjan van de Ven wrote: > On Thu, 18 Oct 2007 09:55:04 -0700 (PDT) > Linus Torvalds <[EMAIL PROTECTED]> wrote: > > > > > > > On Thu, 18 Oct 2007, Jens Axboe wrote: > > > - unsigned long addr = page_to_phys(s->page) + > > > s->offset; > > > + unsigned long addr = page_to_phys(sg_page(s)) + > > > s->offset; > > > > Umm. May I suggest (I haven't read the whole thread yet, maybe > > somebody else already did) that > > > > static inline unsigned long sg_phys(struct scatterlist *sg) > > { > > return page_to_phys(sg_page(sg)) + sg->offset; > > } > > > > would be a good thing to have? > > > > Very few drivers should care so much about the *page* itself (or the > > offset). That's something that the generic allocation code etc cares > > about, but the driver is almost bound to care mostly about the actual > > DMA address > > .... but will that work for systems with IOMMU ? or is it fundamentally > the wrong interface
They use foo_to_bus() on the address. sg_phys() should of course only be used where the user previously did page_to_phys() on the sg page. -- Jens Axboe - 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/