Commits
Tejun Heo committed 18808354b79
percpu_ref: unify staggered atomic switching wait behavior When an atomic or percpu switching starts before the previous atomic switching finishes, the taken behaviors are * If the new atomic switching has confirmation callback, it waits for the previous atomic switching to complete. * If the new percpu switching is the first percpu switching following the previous atomic switching, it waits the previous atomic switching to complete. No percpu_ref user depends on these subtleties. The only meaningful part is that, if the caller ensures that atomic switching isn't in progress, mode switching operations can be issued from any context. This patch pulls the wait logic to the top of both switching functions so that they always wait for the previous atomic switching to complete. This makes the behavior simpler and consistent for both directions and will help allowing concurrent invocations of mode switching functions. Signed-off-by: Tejun Heo <tj@kernel.org>