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Date: Tue, 21 Apr 2026 22:49:54 +0300
From: Leon Romanovsky <leon@kernel.org>
To: Matt Evans <mattev@meta.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Logan Gunthorpe <logang@deltatee.com>,
	Ankit Agrawal <ankita@nvidia.com>,
	Alex Williamson <alex@shazbot.org>,
	Niklas Schnelle <schnelle@linux.ibm.com>, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for
 non_mappable_bars
Message-ID: <20260421194954.GA28413@unreal>
References: <20260421174351.3897842-1-mattev@meta.com>
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In-Reply-To: <20260421174351.3897842-1-mattev@meta.com>

On Tue, Apr 21, 2026 at 10:43:51AM -0700, Matt Evans wrote:
> Extend pcim_p2pdma_provider()'s checks to exclude functions that have
> pdev->non_mappable_bars set.
> 
> Consumers such as VFIO were previously able to map these for access by
> the CPU or P2P.  Update the comment on non_mappable_bars to show it
> refers to any access, not just userspace CPU access.
> 
> Fixes: 372d6d1b8ae3c ("PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation")

I don't object to the patch, but this Fixes line doesn't look correct.
non_mappable_bars applies only to s390, which doesn't support p2p. That
wasn't prevented before 372d6d1b8ae3c refactoring too.

Thanks