On Fri 18-05-18 09:00:29, Dan Williams wrote: > On Fri, May 18, 2018 at 2:46 AM, Christoph Hellwig <hch@xxxxxx> wrote: > >> + select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED) > > > > Btw, what was the reason again we couldn't get rid of FS_DAX_LIMITED? > > The last I heard from Gerald they were still mildly interested in > keeping the dccssblk dax support going with this limited mode, and > threatened to add full page support at a later date: > > --- > From: Gerald > > dcssblk seems to work fine, I did not see any SIGBUS while "executing > in place" from dcssblk with the current upstream kernel, maybe because > we only use dcssblk with fs dax in read-only mode. > > Anyway, the dcssblk change is fine with me. I will look into adding > struct pages for dcssblk memory later, to make it work again with > this change, but for now I do not know of anyone needing this in the > upstream kernel. > > https://www.spinics.net/lists/linux-xfs/msg14628.html > --- We definitely do have customers using "execute in place" on s390x from dcssblk. I've got about two bug reports for it when customers were updating from old kernels using original XIP to kernels using DAX. So we need to keep that working. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
