On Wed, Nov 18 2020 at 4:24pm -0500, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > On Wed, 18 Nov 2020, Mike Snitzer wrote: > > > On Wed, Nov 18 2020 at 10:49am -0500, > > Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > > > I don't think my suggestion will help.. given it'd still leave > > > persistent_memory_claim() without a return statement. > > > > > > Think it worthwhile to just add a dummy 'return 0;' after the BUG(). > > > > Decided to go with this, now staged for 5.11: > > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.11&id=a1e4865b4dda7071f3707f7e551289ead66e38b1 > > Hi > > I would just use "return -EOPNOTSUPP;" and drop the "#ifdef > DM_WRITECACHE_HAS_PMEM" that you added. > > That BUG/return -EOPNOTSUPP code can't happen at all - if > DM_WRITECACHE_HAS_PMEM is not defined, WC_MODE_PMEM(wc) always returns > false - so persistent_memory_claim and BUG() can't ever be called. And if > it can't be called, you don't need to add a code that prints an error in > that case. > > If we don't have DM_WRITECACHE_HAS_PMEM, the compiler optimizer will > remove all the code guarded with if (WC_MODE_PMEM(wc)) as unreachable. > > Mikulas Fair enough.
