Re: [BUG] x86_64 pci_map_sg modifies sg list - fails multiple map/unmaps

[Berkley Shands <berkley@cs.wustl.edu>]

	   		BUG_ON(s->length == 0);

		size += s->length; 

		/* Handle the previous not yet processed entries */

		if (i > start) {
			struct scatterlist *ps = &sg[i-1];
			/* Can only merge when the last chunk ends on a page 
			   boundary. */
			if (1 || !force_iommu || !need || (i-1 > start && ps->offset) ||
			    (ps->offset + ps->length) % PAGE_SIZE) { 
				if (pci_map_cont(sg, start, i, sg+out, pages, 
						 need) < 0)
					goto error;

If I totally disable coalescing, in arch/x86_64/pci-gart.c by adding the if (1 || ...
then the bughalt goes away. So might some performance, but a system that runs is
MUCH better than one that hard faults on a regular basis.

The shipped scsi driver still needs to be updated to NOT "offline" the drives.
the 2.0.5 driver does this quite well.

Thank you.

berkley