[dm-devel] [PATCH 3/7] dm-crypt: avoid deadlock in mempools

[Mike Snitzer]

On Mon, Feb 16 2015 at  4:31am -0500,
Milan Broz <mbroz at redhat.com> wrote:

> On 02/14/2015 02:14 AM, Mike Snitzer wrote:
> > On Fri, Feb 13 2015 at  5:09P -0500,
> > Mikulas Patocka <mpatocka at redhat.com> wrote:
> > 
> >>
> >>
> >> On Fri, 13 Feb 2015, Mike Snitzer wrote:
> >>
> >>>   * In order to not degrade performance with excessive locking, we try
> >>> - * non-blocking allocations without a mutex first and if it fails, we fallback
> >>> + * non-blocking allocation without a mutex first and if it fails, we fallback
> >>>   * to a blocking allocation with a mutex.
> >>>   */
> >>>  static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
> >>
> >> There are multiple allocations, so I would leave plural there.
> > 
> > Fixed, and tweaked the headers (already did that last time around so
> > nothing new, you just didn't pick up my headers for your v2).  I pushed
> > your patchset to linux-next (for 3.21), see:
> > https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/log/?h=for-next
> > 
> > Ondrej and Milan, please let us know if you hit any problems with this
> > patchset and/or branch.
> 
> Will try to test it soon on some strange configurations :)

OK, see if you and Ondrej can re-test with urgency over the next few
days.
 
> Just to be sure - nothing of this patchset is planned for 3.20?
> 
> (TBH I would like to see it upstream asap but too late for 3.20 here I guess...)

I'm not opposed to sending them for the current merge (we still have a
week) purely because this code has been around for quite a long time
and is overdue for landing upstream.  Mikulas' recent change is
localized to adding the knob to shutoff offloading write bios to a
separate thread -- so nothing that should invalidate prior testing, etc.

Let me know what you guys think and please share results.  If we have
the results ideally we can decide by end of day Thursday.

I will rebase real quick to get these changes at the front of the
dm-for-3.20 followon work.

Mike