From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
arnd@arndb.de, "Yu, Fenghua" <fenghua.yu@intel.com>,
gregkh@linuxfoundation.org, iommu@lists.linux-foundation.org,
zhangfei.gao@linaro.org, linux-accelerators@lists.ozlabs.org
Subject: Re: [PATCH 0/2] iommu: Remove iommu_sva_ops::mm_exit()
Date: Thu, 9 Apr 2020 09:08:21 -0300 [thread overview]
Message-ID: <20200409120821.GE11886@ziepe.ca> (raw)
In-Reply-To: <20200408164802.155a69e3@jacob-builder>
On Wed, Apr 08, 2020 at 04:48:02PM -0700, Jacob Pan wrote:
> > Yes, this is the proper way, when the DMA is stopped and no use of the
> > PASID remains then you can drop the mmu notifier and release the PASID
> > entirely. If that is linked to the lifetime of the FD then forget
> > completely about the mm_struct lifetime, it doesn't matter..
> >
> Got everything above, thanks a lot.
>
> If everything is in order with the FD close. Why do we need to
> "ask IOMMU drivers to silently abort DMA and Page Requests in the
> meantime." in mm_exit notifier? This will be done orderly in unbind
> anyway.
I thought this is exactly what Jean-Phillippe is removing here, it is
a bad idea for the reasons he explained.
> > > Enforcing unbind upon FD close might be a precarious path, perhaps
> > > that is why we have to deal with out of order situation?
> >
> > How so? You just put it in the FD release function :)
>
> I was thinking some driver may choose to defer unbind in some workqueue
> etc.
Doesn't really change anything, the lifetime of the PASID wouuld be
the lifetime of the notifier and the bind, and DMA can't continue
without the notifier registered.
Jason
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-04-09 12:08 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 14:04 [PATCH 0/2] iommu: Remove iommu_sva_ops::mm_exit() Jean-Philippe Brucker
2020-04-08 14:04 ` [PATCH 1/2] uacce: Remove mm_exit() op Jean-Philippe Brucker
2020-04-09 9:07 ` Zhangfei Gao
2020-04-09 9:44 ` Jean-Philippe Brucker
2020-04-08 14:04 ` [PATCH 2/2] iommu: Remove iommu_sva_ops::mm_exit() Jean-Philippe Brucker
2020-04-08 18:35 ` [PATCH 0/2] " Jacob Pan
2020-04-08 19:02 ` Jason Gunthorpe
2020-04-08 21:35 ` Jacob Pan
2020-04-08 22:32 ` Jason Gunthorpe
2020-04-08 23:48 ` Jacob Pan
2020-04-09 6:39 ` Jean-Philippe Brucker
2020-04-09 14:14 ` Jacob Pan
2020-04-09 14:25 ` Jason Gunthorpe
2020-04-09 16:21 ` Jacob Pan
2020-04-09 16:58 ` Jason Gunthorpe
2020-04-09 14:50 ` Jean-Philippe Brucker
2020-04-09 16:27 ` Jacob Pan
2020-04-10 15:52 ` Jacob Pan
2020-04-15 7:47 ` Jean-Philippe Brucker
2020-04-16 20:58 ` Jacob Pan
2020-04-20 8:02 ` Jean-Philippe Brucker
2020-04-09 12:08 ` Jason Gunthorpe [this message]
2020-04-09 16:31 ` Jacob Pan
2020-04-08 23:49 ` Fenghua Yu
2020-04-09 12:12 ` Jason Gunthorpe
2020-04-08 19:04 ` Jason Gunthorpe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200409120821.GE11886@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=arnd@arndb.de \
--cc=fenghua.yu@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@linux.intel.com \
--cc=jean-philippe@linaro.org \
--cc=linux-accelerators@lists.ozlabs.org \
--cc=zhangfei.gao@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).