Messages in this thread | | | From | Dan Williams <> | Date | Tue, 1 Aug 2017 14:19:50 -0700 | Subject | Re: dm: enable opt-out of device-mapper dax support |
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On Tue, Aug 1, 2017 at 2:04 PM, Bart Van Assche <Bart.VanAssche@wdc.com> wrote: > On Tue, 2017-08-01 at 13:59 -0700, Dan Williams wrote: >> On Tue, Aug 1, 2017 at 12:45 PM, Dan Williams <dan.j.williams@intel.com> wrote: >> > On Tue, Aug 1, 2017 at 12:02 PM, Mike Snitzer <snitzer@redhat.com> wrote: >> > > On Tue, Aug 01 2017 at 2:12pm -0400, >> > > Dan Williams <dan.j.williams@intel.com> wrote: >> > > > [ ... ] >> > > >> > > I'm questioning the need to have yet another Kbuild CONFIG option. If >> > > the user has enabled CONFIG_BLK_DEV_PMEM and CONFIG_FS_DAX (DAX already >> > > gets selected by CONFIG_FS_DAX) then shouldn't the DM capabilities just >> > > be enabled? >> > > >> > > Guess I'm just skeptical of: why do we want to move to a model where >> > > users need to opt-in to DM support for DAX? >> > > >> > > I also _really_ don't like each target's DAX support being colocated in >> > > drivers/md/dm-dax.c >> > > >> > > This all looks and feels like a serious step backwards. >> > >> > Ok, you want ifdef'd sections of DAX code in each target and make >> > DM_DAX a silent option that gets enabled with BLK_DEV_PMEM, anything >> > else? >> >> Actually, no, I was thrown off by Bart's suggestion to move code >> around. I can handle this all by deleting "select DAX" and adding more >> stubbed out dax helpers. > > Hello Mike and Dan, > > How about one *-dax.c file per *.c dm file that has to be modified to add DAX support? > I think that approach would avoid collocation of code for different targets in a > single dm-dax.c file and would also avoid that #ifdef CONFIG_DAX statements have to > be added. This approach is orthogonal to removal of CONFIG_DM_DAX.
You're free to send an alternative approach, but the new ifdefs in include/linux/dax.h seem to be the cleanest option to remove dax text size when the device-mapper dax support is not needed.
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