On Wed, Sep 21, 2022 at 08:48:22AM -0700, Dan Williams wrote: > The fsdax core now manages pgmap references when servicing faults that > install new mappings, and elevates the page reference until it is > zapped. It coordinates with the VFS to make sure that all page > references are dropped before the hosting inode goes out of scope > (iput_final()). > > In order to delete the unnecessary pgmap reference taking in mm/gup.c > devdax needs to move to the same model. I think this patch is more about making devdax and fsdax use the same set of functions and logic so that when it gets to patch 16/17 devdax doesn't break. That understanding matches the first paragraph, at least. I would delete the remark about gup since it is really patch 17 that allows gup to be fixed by making it so that refcount == 0 means not to look at the pgmap (instead of refcount == 1 as is now) ? Jason
