On Tue, Sep 15 2020 at 3:49pm -0400, Dan Williams <dan.j.willi...@intel.com> wrote:
> On Tue, Sep 15, 2020 at 1:01 AM Jan Kara <j...@suse.cz> wrote: > > > > Hi! > > > > On Tue 15-09-20 11:03:29, col...@suse.de wrote: > > > Could you please to take a look? I am offline in the next two weeks. > > > > I just had a look into this. IMHO the justification in 6180bb446a "dax: fix > > detection of dax support for non-persistent memory block devices" is just > > bogus and people got confused by the previous condition > > > > if (!dax_dev && !bdev_dax_supported(bdev, blocksize)) > > > > which was bogus as well. bdev_dax_supported() always returns false for bdev > > that doesn't have dax_dev (naturally so). So in the original condition > > there was no point in calling bdev_dax_supported() if we know dax_dev is > > NULL. > > > > Then this was changed to: > > > > if (!dax_dev || !bdev_dax_supported(bdev, blocksize)) > > > > which looks more sensible at the first sight. But only at the first sight - > > if you look at wider context, __generic_fsdax_supported() is the bulk of > > code that decides whether a device supports DAX so calling > > bdev_dax_supported() from it indeed doesn't look as such a great idea. So > > IMO the condition should be just: > > > > if (!dax_dev) > > > > I'll send a fix for this. > > If you beat me to it, great, but you might be sleeping now. I agree > the original condition was bogus and looks to be a result of previous > non-thorough refactoring on my part. I think we can move that !dax_dev > into dax_supported(). I'll take a look. You trimmed the relevant portion of Jan's reply but: can you also weigh-in one whether DM is using the wrong function to test for DAX? Mike _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-le...@lists.01.org
