libceph: Avoid holding the zero page on ceph_msgr_slab_init errors
libceph: Avoid holding the zero page on ceph_msgr_slab_init errors

ceph_msgr_slab_init may fail due to a temporary ENOMEM.

Delay a bit the initialization of zero_page in ceph_msgr_init and
reorder its cleanup in _ceph_msgr_exit so it's done in reverse
order of setup.

BUG_ON() will not suffer to be postponed in case it is triggered.

Signed-off-by: Benoît Canet <4995c48823b6dddcd038b28925b705cbe6043fa2@nodalink.com>
Reviewed-by: Alex Elder <f429030cf5c0faf36fac3d102073b6e63a647baa@linaro.org>
Signed-off-by: Ilya Dryomov <152d4c5bebf13a5b809d42b4d789cf9d887e6698@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs