Mathieu Desnoyers wrote: > In preparation for checking whether the architecture has data cache > aliasing within alloc_dax(), modify the error handling of dm alloc_dev() > to treat alloc_dax() -EOPNOTSUPP failure as non-fatal. > > For the transition, consider that alloc_dax() returning NULL is the > same as returning -EOPNOTSUPP. > > Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing > caches") > Suggested-by: Dan Williams <dan.j.willi...@intel.com> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> > Cc: Alasdair Kergon <a...@redhat.com> > Cc: Mike Snitzer <snit...@kernel.org> > Cc: Mikulas Patocka <mpato...@redhat.com> > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Linus Torvalds <torva...@linux-foundation.org> > Cc: Dan Williams <dan.j.willi...@intel.com> > Cc: Vishal Verma <vishal.l.ve...@intel.com> > Cc: Dave Jiang <dave.ji...@intel.com> > Cc: Matthew Wilcox <wi...@infradead.org> > Cc: Arnd Bergmann <a...@arndb.de> > Cc: Russell King <li...@armlinux.org.uk> > Cc: linux-a...@vger.kernel.org > Cc: linux-...@vger.kernel.org > Cc: linux-fsde...@vger.kernel.org > Cc: linux...@kvack.org > Cc: linux-...@vger.kernel.org > Cc: dm-devel@lists.linux.dev > Cc: nvd...@lists.linux.dev > --- > drivers/md/dm.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 23c32cd1f1d8..2fc22cae9089 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -2054,6 +2054,7 @@ static void cleanup_mapped_device(struct mapped_device > *md) > static struct mapped_device *alloc_dev(int minor) > { > int r, numa_node_id = dm_get_numa_node(); > + struct dax_device *dax_dev; > struct mapped_device *md; > void *old_md; > > @@ -2122,15 +2123,15 @@ static struct mapped_device *alloc_dev(int minor) > md->disk->private_data = md; > sprintf(md->disk->disk_name, "dm-%d", minor); > > - if (IS_ENABLED(CONFIG_FS_DAX)) { > - md->dax_dev = alloc_dax(md, &dm_dax_ops); > - if (IS_ERR(md->dax_dev)) { > - md->dax_dev = NULL; > + dax_dev = alloc_dax(md, &dm_dax_ops); > + if (IS_ERR_OR_NULL(dax_dev)) {
Similar feedback as the pmem change, lets not propagate the mistake that alloc_dax() could return NULL, none of the callers of alloc_dax() properly handled NULL and it was just luck that none of the use cases tried to use alloc_dax() in the CONFIG_DAX=n case.