Tejun Heo 6810e4a394 percpu_ref: remove unnecessary ACCESS_ONCE() in percpu_ref_tryget_live() ... __ref_is_percpu() needs the implied ACCESS_ONCE() in lockless_dereference() on @ref->percpu_count_ptr because the value is tested for !__PERCPU_REF_ATOMIC, which may be set asynchronously, and then used as a pointer. If the compiler generates a separate fetch when using it as a pointer, __PERCPU_REF_ATOMIC may be set in between contaminating the pointer value. percpu_ref_tryget_live() also uses ACCESS_ONCE() to test __PERCPU_REF_DEAD; however, there's no reason for this. I just copied ACCESS_ONCE() usage blindly from __ref_is_percpu(). All it does is confusing people trying to understand what's going on. This patch removes the unnecessary ACCESS_ONCE() usage from percpu_ref_tryget_live() and adds a comment explaining why __ref_is_percpu() needs it. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kent Overstreet <kmo@daterainc.com>		2015-01-06 10:26:10 -05:00
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dt-bindings	Please consider pulling the clk framework changes toward 3.19. It is	2014-12-20 16:42:36 -08:00
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linux	percpu_ref: remove unnecessary ACCESS_ONCE() in percpu_ref_tryget_live()	2015-01-06 10:26:10 -05:00
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