linux-kernel - Re: [PATCH 05/12] mm: Remove remaining uses of PFN

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Message-ID: <20250603133837.GF386142@ziepe.ca>
Date: Tue, 3 Jun 2025 10:38:37 -0300
From: Jason Gunthorpe <jgg@...pe.ca>
To: Alistair Popple <apopple@...dia.com>
Cc: linux-mm@...ck.org, gerald.schaefer@...ux.ibm.com,
	dan.j.williams@...el.com, willy@...radead.org, david@...hat.com,
	linux-kernel@...r.kernel.org, nvdimm@...ts.linux.dev,
	linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
	linux-xfs@...r.kernel.org, jhubbard@...dia.com, hch@....de,
	zhang.lyra@...il.com, debug@...osinc.com, bjorn@...nel.org,
	balbirs@...dia.com, lorenzo.stoakes@...cle.com,
	linux-arm-kernel@...ts.infradead.org, loongarch@...ts.linux.dev,
	linuxppc-dev@...ts.ozlabs.org, linux-riscv@...ts.infradead.org,
	linux-cxl@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	John@...ves.net
Subject: Re: [PATCH 05/12] mm: Remove remaining uses of PFN_DEV

On Thu, May 29, 2025 at 04:32:06PM +1000, Alistair Popple wrote:
> PFN_DEV was used by callers of dax_direct_access() to figure out if the
> returned PFN is associated with a page using pfn_t_has_page() or
> not. However all DAX PFNs now require an assoicated ZONE_DEVICE page so can
> assume a page exists.
> 
> Other users of PFN_DEV were setting it before calling
> vmf_insert_mixed(). This is unnecessary as it is no longer checked, instead
> relying on pfn_valid() to determine if there is an associated page or not.
> 
> Signed-off-by: Alistair Popple <apopple@...dia.com>
> Reviewed-by: Christoph Hellwig <hch@....de>
> ---
>  drivers/gpu/drm/gma500/fbdev.c     |  2 +-
>  drivers/gpu/drm/omapdrm/omap_gem.c |  5 ++---
>  drivers/s390/block/dcssblk.c       |  3 +--
>  drivers/vfio/pci/vfio_pci_core.c   |  6 ++----
>  fs/cramfs/inode.c                  |  2 +-
>  include/linux/pfn_t.h              | 25 ++-----------------------
>  mm/memory.c                        |  4 ++--
>  7 files changed, 11 insertions(+), 36 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Jason