* Re: Patch "dm: ensure bio submission follows a depth-first tree walk" has been added to the 4.15-stable tree
2018-03-22 13:47 ` Patch "dm: ensure bio submission follows a depth-first tree walk" has been added to the 4.15-stable tree Mike Snitzer
@ 2018-03-22 13:56 ` Mikulas Patocka
2018-03-22 14:01 ` Greg KH
1 sibling, 0 replies; 3+ messages in thread
From: Mikulas Patocka @ 2018-03-22 13:56 UTC (permalink / raw)
To: Mike Snitzer
Cc: gregkh, neilb, alexander.levin, stable, stable-commits, dm-devel
I agree.
The patch "dm: ensure bio submission follows a depth-first tree walk"
doesn't really fix any bug (and it may introduce new bugs), so it isn't
applicable to the stable kernel branches.
The kernel 4.15 and below have a "dm_offload" mechanism that avoids the
possible deadlocks in dm, there is no reason why this should be converted
to the "depth-first tree walk".
Mikulas
On Thu, 22 Mar 2018, Mike Snitzer wrote:
> On Thu, Mar 22 2018 at 9:06am -0400,
> gregkh@linuxfoundation.org <gregkh@linuxfoundation.org> wrote:
>
> >
> > This is a note to let you know that I've just added the patch titled
> >
> > dm: ensure bio submission follows a depth-first tree walk
> >
> > to the 4.15-stable tree which can be found at:
> > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> >
> > The filename of the patch is:
> > dm-ensure-bio-submission-follows-a-depth-first-tree-walk.patch
> > and it can be found in the queue-4.15 subdirectory.
> >
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
>
> The following applies to 4.14 stable@ too.
>
> I think it very questionable to pull this into stable trees. How'd it
> even elevate to be considered for stable@?
>
> But if you do, you definitely need this additional upstream commit:
> 8dd601fa8317 ("dm: correctly handle chained bios in dec_pending()")
>
> Even with that I'm not excited about supporting some partial backport of
> these changes because there were a lot more related changes -- only
> taking a subset makes these stable@ kernels unicorns.. I deal with
> enough unicorn vendor kernels (but on my terms, with my control over
> what is "supportable"):
>
> Anyway, other related commits are:
> 80cd17578310 dm crypt: remove BIOSET_NEED_RESCUER flag
> c110a4b6e603 dm io: remove BIOSET_NEED_RESCUER flag from bios bioset
> f31c21e4365c dm: remove unused 'num_write_bios' target interface
> 318716ddea08 dm: safely allocate multiple bioset bios
> 4a3f54d94d5c dm: remove BIOSET_NEED_RESCUER based dm_offload infrastructure
> 0776aa0e30aa dm: ensure bio-based DM's bioset and io_pool support targets' maximum IOs
> 3d7f45625a84 dm: fix __send_changing_extent_only() to send first bio and chain remainder
>
> So NAK from me. If others have a compelling argument I'm open to
> considering.
>
> Mike
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Patch "dm: ensure bio submission follows a depth-first tree walk" has been added to the 4.15-stable tree
2018-03-22 13:47 ` Patch "dm: ensure bio submission follows a depth-first tree walk" has been added to the 4.15-stable tree Mike Snitzer
2018-03-22 13:56 ` Mikulas Patocka
@ 2018-03-22 14:01 ` Greg KH
1 sibling, 0 replies; 3+ messages in thread
From: Greg KH @ 2018-03-22 14:01 UTC (permalink / raw)
To: Mike Snitzer
Cc: neilb, alexander.levin, stable, stable-commits, dm-devel,
Mikulas Patocka
On Thu, Mar 22, 2018 at 09:47:59AM -0400, Mike Snitzer wrote:
> On Thu, Mar 22 2018 at 9:06am -0400,
> gregkh@linuxfoundation.org <gregkh@linuxfoundation.org> wrote:
>
> >
> > This is a note to let you know that I've just added the patch titled
> >
> > dm: ensure bio submission follows a depth-first tree walk
> >
> > to the 4.15-stable tree which can be found at:
> > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> >
> > The filename of the patch is:
> > dm-ensure-bio-submission-follows-a-depth-first-tree-walk.patch
> > and it can be found in the queue-4.15 subdirectory.
> >
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
>
> The following applies to 4.14 stable@ too.
>
> I think it very questionable to pull this into stable trees. How'd it
> even elevate to be considered for stable@?
>
> But if you do, you definitely need this additional upstream commit:
> 8dd601fa8317 ("dm: correctly handle chained bios in dec_pending()")
>
> Even with that I'm not excited about supporting some partial backport of
> these changes because there were a lot more related changes -- only
> taking a subset makes these stable@ kernels unicorns.. I deal with
> enough unicorn vendor kernels (but on my terms, with my control over
> what is "supportable"):
>
> Anyway, other related commits are:
> 80cd17578310 dm crypt: remove BIOSET_NEED_RESCUER flag
> c110a4b6e603 dm io: remove BIOSET_NEED_RESCUER flag from bios bioset
> f31c21e4365c dm: remove unused 'num_write_bios' target interface
> 318716ddea08 dm: safely allocate multiple bioset bios
> 4a3f54d94d5c dm: remove BIOSET_NEED_RESCUER based dm_offload infrastructure
> 0776aa0e30aa dm: ensure bio-based DM's bioset and io_pool support targets' maximum IOs
> 3d7f45625a84 dm: fix __send_changing_extent_only() to send first bio and chain remainder
>
> So NAK from me. If others have a compelling argument I'm open to
> considering.
Thanks for letting me know, I've now dropped this from the 4.15.y,
4.14.y, and 4.9.y stable patch queues.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread