On 2022-09-23 16:58, Jason Gunthorpe wrote: > On Fri, Sep 23, 2022 at 02:11:03PM -0600, Logan Gunthorpe wrote: >> >> >> On 2022-09-23 13:53, Jason Gunthorpe wrote: >>> On Fri, Sep 23, 2022 at 01:08:31PM -0600, Logan Gunthorpe wrote: >>> I'm encouraging Dan to work on better infrastructure in pgmap core >>> because every pgmap implementation has this issue currently. >>> >>> For that reason it is probably not so relavent to this series. >>> >>> Perhaps just clarify in the commit message that the FOLL_LONGTERM >>> restriction is to copy DAX until the pgmap page refcounts are fixed. >> >> Ok, I'll add that note. >> >> Per the fix for the try_grab_page(), to me it doesn't fit well in >> try_grab_page() without doing a bunch of cleanup to change the >> error handling, and the same would have to be added to try_grab_folio(). >> So I think it's better to leave it where it was, but move it below the >> respective grab calls. Does the incremental patch below look correct? > > Oh? I was thinking of just a very simple thing: Really would like it to return -EREMOTEIO instead of -ENOMEM as that's the error used for bad P2PDMA page everywhere. Plus the concern that some of the callsites of try_grab_page() might not have a get or a pin and thus it's not safe which was the whole point of the change anyway. Plus we have to do the same for try_grab_folio(). Logan
