Messages in this thread |  | | | Date | Thu, 18 Oct 2007 05:03:27 -0700 (PDT) | | Subject | Re: [bug] block subsystem related crash with latest -git | | From | David Miller <> |
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From: Jens Axboe <jens.axboe@oracle.com> Date: Thu, 18 Oct 2007 12:55:17 +0200
> Things have progressed a lot since, see my recent posting based on > Davem's proposal. Will post another patch soonish, that is also > tested.
One core issue here is that we need to decide whether this thing to be iterated like an array or like a linked list. It's trying to be both.
If we decide upon a looping construct for consumers and stick to it, we'll be in much better shape than we are now and bugs will be eaiser to spot. It would be so much simpler to audit if all we saw in the consumers were things like:
while (sg) { do_stuff(sg); sg = sg_next(sg); } I would suggest that we just get it over with and convert the whole tree now rather than trying to do this kind of thing in stages. Because then we can say that ever scatterlist creator has to set the "end" bit and therefore you use well established patterns for scatterlist iteration such as "traverse sg_next() until NULL" as shown above.
I also noticed that there is the issue of on-stack and embedded scatterlist users. We'll need some sort of "DECLARE_SCATTERLIST" and a "scatterlist_init()" thing so that we can keep DEBUG_SG working even in those cases. But for all I know Jens could be working on that already :-)
The only other real option if we don't convert the whole tree now to the "end" marker stuff, is to enforce that every scatterlist iterator only traverse the number of entries there were told are in the one given to them. - 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/
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