On 25.09.24 00:59, Dan Williams wrote:
The dcssblk driver has long needed special case supoprt to enable limited dax operation, so called CONFIG_FS_DAX_LIMITED. This mode works around the incomplete support for ZONE_DEVICE on s390 by forgoing the ability of dax-mapped pages to support GUP. Now, pending cleanups to fsdax that fix its reference counting [1] depend on the ability of all dax drivers to supply ZONE_DEVICE pages. To allow that work to move forward, dax support needs to be paused for dcssblk until ZONE_DEVICE support arrives. That work has been known for a few years [2], and the removal of "pte_devmap" requirements [3] makes the conversion easier. For now, place the support behind CONFIG_BROKEN, and remove PFN_SPECIAL (dcssblk was the only user). Link: http://lore.kernel.org/cover.9f0e45d52f5cff58807831b6b867084d0b14b61c.1725941415.git-series.apopple@xxxxxxxxxx [1] Link: http://lore.kernel.org/20210820210318.187742e8@thinkpad/ [2] Link: http://lore.kernel.org/4511465a4f8429f45e2ac70d2e65dc5e1df1eb47.1725941415.git-series.apopple@xxxxxxxxxx [3] Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> Cc: Sven Schnelle <svens@xxxxxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Alistair Popple <apopple@xxxxxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> ---
Acked-by: David Hildenbrand <david@xxxxxxxxxx> -- Cheers, David / dhildenb
