Re: [PATCH v8 00/11] Fix BUG_ON in vfio_iommu_group_notifier()

From: Joerg Roedel <joro@8bytes.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Christoph Hellwig <hch@infradead.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	rafael@kernel.org, Diana Craciun <diana.craciun@oss.nxp.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Stuart Yoder <stuyoder@gmail.com>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Li Yang <leoyang.li@nxp.com>, Dmitry Osipenko <digetx@gmail.com>,
	iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 00/11] Fix BUG_ON in vfio_iommu_group_notifier()
Date: Fri, 8 Apr 2022 17:37:16 +0200	[thread overview]
Message-ID: <YlBWrE7kxX9vraOD@8bytes.org> (raw)
In-Reply-To: <20220408141747.GZ2120790@nvidia.com>

On Fri, Apr 08, 2022 at 11:17:47AM -0300, Jason Gunthorpe wrote:
> You might consider using a linear tree instead of the topic branches,
> topics are tricky and I'm not sure it helps a small subsystem so much.
> Conflicts between topics are a PITA for everyone, and it makes
> handling conflicts with rc much harder than it needs to be.

I like the concept of a branch per driver, because with that I can just
exclude that branch from my next-merge when there are issues with it.
Conflicts between branches happen too, but they are quite manageable
when the branches have the same base.

Overall I am thinking of reorganizing the IOMMU tree, but it will likely
not end up to be a single-branch tree, although the number of patches
per cycle _could_ just be carried in a single branch.

> At least I haven't felt a need for topics while running larger trees,
> and would find it stressful to try and squeeze the entire patch flow
> into only 3 weeks out of the 7 week cycle.

Yeah, so it is 4 weeks in an 9 weeks cycle :) The merge window is 2
weeks and not a lot happens. The 2 weeks after are for stabilization and
I usually only pick up fixes. Then come the 4 weeks were new code gets
into the tree. In the last week everything gets testing in linux-next to
be ready for the merge window. I will pickup fixes in that week, of
course.

> In any event, I'd like this on a branch so Alex can pull it too, I
> guess it means Alex has to merge rc3 to VFIO as well?

Sure, I can put these patches in a separate branch for Alex to pull into
the VFIO tree.

Regards,

	Joerg