Re: AMD-Vi IO_PAGE_FAULTs and ata3.00: failed command: READ FPDMA QUEUED errors since Linux 4.0

[Jeff Moyer <jmoyer@redhat.com>]

Mike Snitzer <snitzer@redhat.com> writes:

> On Mon, Aug 03 2015 at  4:12am -0400,
> Joerg Roedel <joro@8bytes.org> wrote:
>
>> On Sun, Aug 02, 2015 at 08:48:06PM +0200, Andreas Hartmann wrote:
>> > >>https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=34b48db66e08ca1c1bc07cf305d672ac940268dc
>> > >>
>> > >>block: remove artifical max_hw_sectors cap
>> 
>> Looking at the patch, it seems to me that it just uncovered a bug
>> elsewhere. It looks like an underlying driver doesn't expect the
>> big io-requests that the patch enables and does not dma-map the whole
>> target buffer, causing the IO_PAGE_FAULTs later.
>
> That patch has caused issues elsewhere too, see this 'Revert "block:
> remove artifical max_hw_sectors cap"' thread (if/when lkml.org
> cooperates): https://lkml.org/lkml/2015/7/20/572
>
> But it could be that there is a need for a horkage fix for this specific
> hardware? something comparable to this?:
> http://git.kernel.org/linus/af34d637637eabaf49406eb35c948cd51ba262a6
>
> We are running out of time to fix these whack-a-mole issues in 4.2
> though.

CC-ing linux-ide.  Original dm-devel posting:
  https://www.redhat.com/archives/dm-devel/2015-July/msg00178.html

Andreas, I would be curious to know what the value of
/sys/block/sdX/queue/max_hw_sectors_kb is for the affected disks.

Cheers,
Jeff