percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky

Currently, a percpu_ref which is initialized with
PERPCU_REF_INIT_ATOMIC or switched to atomic mode via
switch_to_atomic() automatically reverts to percpu mode on the first
percpu_ref_reinit().  This makes the atomic mode difficult to use for
cases where a percpu_ref is used as a persistent on/off switch which
may be cycled multiple times.

This patch makes such atomic state sticky so that it survives through
kill/reinit cycles.  After this patch, atomic state is cleared only by
an explicit percpu_ref_switch_to_percpu() call.

Signed-off-by: Tejun Heo <[email protected]>
Reviewed-by: Kent Overstreet <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Johannes Weiner <[email protected]>

0 files changed, 0 insertions, 0 deletions