gcc warns about an empty body in an else statement:

drivers/dax/bus.c: In function 'do_id_store':
drivers/dax/bus.c:94:48: error: suggest braces around empty body in an 'else' statement [-Werror=empty-body]
   94 |                         /* nothing to remove */;
      |                                                ^
drivers/dax/bus.c:99:43: error: suggest braces around empty body in an 'else' statement [-Werror=empty-body]
   99 |                 /* dax_id already added */;
      |                                           ^

In both of these cases, the 'else' exists only to have a place to
add a comment, but that comment doesn't really explain that much
either, so the easiest way to shut up that warning is to just
remove the else.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210322114514.3490752-1-arnd@kernel.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pull misc vfs updates from Al Viro:
 "Assorted stuff pile - no common topic here"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  whack-a-mole: don't open-code iminor/imajor
  9p: fix misuse of sscanf() in v9fs_stat2inode()
  audit_alloc_mark(): don't open-code ERR_CAST()
  fs/inode.c: make inode_init_always() initialize i_ino to 0
  vfs: don't unnecessarily clone write access for writable fds

Pick up device-dax updates to merge with libnvdimm device updates for
5.12.

* Fix the polarity of EINVAL in a sysfs return code
* Drop the unused return code for driver remove() callbacks

several instances creeped back into the tree...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct dax_device_driver::remove()
return void, too. All users already unconditionally return 0, this commit
makes it obvious that returning an error code isn't intended.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-6-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The dax core properly handles a dax driver not having a remove callback.
So drop it without changing the effective behaviour.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-5-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The static variable match_always_count is supposed to track if there is
a driver registered that has .match_always set. If driver_register()
fails, the previous increment must be undone.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-4-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

If all resources are allocated in .probe() using devm_ functions it
might make sense to not provide a .remove() callback. Then the right
thing is to just return success.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-3-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The bus probe function dax_bus_probe() calls the probe callback without
checking it to be non-NULL. Prevent a NULL pointer exception if a driver
without a probe function is registered by refusing to register this
driver.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205222842.34896-2-uwe@kleine-koenig.org
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

All drivers return 0 in their remove callback and the driver core ignores
the return value of nvdimm_bus_remove() anyhow. So simplify by changing
the driver remove callback to return void and return 0 unconditionally
to the upper layer.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210212171043.2136580-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>