On Thu, Feb 06, 2025 at 09:50:07PM -0800, Dan Williams wrote: > Alistair Popple wrote: > > On Mon, Jan 13, 2025 at 07:35:07PM -0800, Dan Williams wrote: > > > Alistair Popple wrote: > > > > [...] > > > > > ...and here is that aformentioned patch: > > > > This patch is different from what you originally posted here: > > https://yhbt.net/lore/linux-s390/172721874675.497781.3277495908107141898.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx/ > > > > > -- 8< -- > > > Subject: dcssblk: Mark DAX broken, remove FS_DAX_LIMITED support > > > > > > From: Dan Williams <dan.j.williams@xxxxxxxxx> > > > > > > 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). > > > > Specifically it no longer removes PFN_SPECIAL. Was this intentional? Or should I > > really have picked up the original patch from the mailing list? > > I think this patch that only removes the dccsblk usage of PFN_SPECIAL is > sufficient. Leave the rest to the pfn_t cleanup. Makes sense. I noticed it when rebaing the pfn_t cleanup because previously it did remove PFN_SPECIAL so was just wondering if it was intentional. I will add a patch removing PFN_SPECIAL to the pfn_t/pXX_devmap cleanup series I'm writing now.
