Messages in this thread |  | | | Date | Mon, 22 Oct 2007 21:39:39 +0200 (CEST) | | From | Geert Uytterhoeven <> | | Subject | Re: [PATCH 09/10] Change table chaining layout |
| |
On Mon, 22 Oct 2007, Jens Axboe 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.
Better safe than sorry...
Is it possible that a chain entry pointer has bit 1 set on architectures (e.g. m68k) where the natural alignment of 32-bit quantities is _2_ bytes, not 4?
Gr{oetje,eeting}s, Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |