On Tue, Sep 24, 2024 at 03:59:08PM -0700, Dan Williams wrote: Hi Dan, > 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] ... > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> > --- > drivers/s390/block/Kconfig | 12 ++++++++++-- > drivers/s390/block/dcssblk.c | 26 +++++++++++++++++--------- > fs/Kconfig | 9 +-------- > fs/dax.c | 12 ------------ > include/linux/pfn_t.h | 15 --------------- > mm/memory.c | 2 -- > mm/memremap.c | 4 ---- > 7 files changed, 28 insertions(+), 52 deletions(-) ... I guess you want to remove dcssblk from Documentation/filesystems/dax.rst. Gerald is back from vacation on Monday and he will likely comment on this. Tested-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> Thanks!
