On Tue, Oct 23 2007, Boaz Harrosh wrote: > On Mon, Oct 22 2007 at 20:11 +0200, Jens Axboe <[EMAIL PROTECTED]> wrote: > > Change the page member of the scatterlist structure to be an unsigned > > long, and encode more stuff in the lower bits: > > > > - Bits 0 and 1 zero: this is a normal sg entry. Next sg entry is located > > at sg + 1. > > - Bit 0 set: this is a chain entry, the next real entry is at ->page_link > > with the two low bits masked off. > > - Bit 1 set: this is the final entry in the sg entry. sg_next() will return > > NULL when passed such an entry. > > > > It's thus important that sg table users use the proper accessors to get > > and set the page member. > > > > Signed-off-by: Jens Axboe <[EMAIL PROTECTED]> > > --- > <snip> > > > > /** > > * sg_set_page - Set sg entry to point at given page > > @@ -20,11 +37,20 @@ > > **/ > > static inline void sg_set_page(struct scatterlist *sg, struct page *page) > > { > > - sg->page = page; > > + unsigned long page_link = sg->page_link & 0x3; > > + > You might want to put a BUG_ON(page & 0x3); Make sure > you're not loosing information. (The m68k problem)
That's a really good idea, thanks Boaz! I'll add that. -- 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/