Mathieu Desnoyers wrote: > In preparation for checking whether the architecture has data cache > aliasing within alloc_dax(), modify the error handling of nvdimm/pmem > pmem_attach_disk() 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") > 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/nvdimm/pmem.c | 26 ++++++++++++++------------ > 1 file changed, 14 insertions(+), 12 deletions(-) > > diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c > index 9fe358090720..f1d9f5c6dbac 100644 > --- a/drivers/nvdimm/pmem.c > +++ b/drivers/nvdimm/pmem.c > @@ -558,19 +558,21 @@ static int pmem_attach_disk(struct device *dev, > disk->bb = &pmem->bb; > > dax_dev = alloc_dax(pmem, &pmem_dax_ops); > - if (IS_ERR(dax_dev)) { > - rc = PTR_ERR(dax_dev); > - goto out; > + if (IS_ERR_OR_NULL(dax_dev)) {
alloc_dax() should never return NULL. I.e. the lead in before this patch should fix this misunderstanding: diff --git a/include/linux/dax.h b/include/linux/dax.h index b463502b16e1..df2d52b8a245 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -86,11 +86,7 @@ static inline void *dax_holder(struct dax_device *dax_dev) static inline struct dax_device *alloc_dax(void *private, const struct dax_operations *ops) { - /* - * Callers should check IS_ENABLED(CONFIG_DAX) to know if this - * NULL is an error or expected. - */ - return NULL; + return ERR_PTR(-EOPNOTSUPP); } static inline void put_dax(struct dax_device *dax_dev) { > + rc = IS_ERR(dax_dev) ? PTR_ERR(dax_dev) : -EOPNOTSUPP; Then this ternary can be replaced with just a check of which PTR_ERR() value is being returned.