rcu: Fix idle-task checks
authorPaul E. McKenney <paul.mckenney@linaro.org>
Wed, 2 Nov 2011 14:38:25 +0000 (07:38 -0700)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Sun, 11 Dec 2011 18:31:44 +0000 (10:31 -0800)
commit11dbaa8cb79a6e4a234a134898436f717a663f01
tree79d18cd1af72016fcc54768388e46253208abe2e
parentaea1b35e29e658d42d7ba2237f3aa7f93e18509d
rcu: Fix idle-task checks

RCU has traditionally relied on idle_cpu() to determine whether a given
CPU is running in the context of an idle task, but commit 908a3283
(Fix idle_cpu()) has invalidated this approach.  After commit 908a3283,
idle_cpu() will return true if the current CPU is currently running the
idle task, and will be doing so for the foreseeable future.  RCU instead
needs to know whether or not the current CPU is currently running the
idle task, regardless of what the near future might bring.

This commit therefore switches from idle_cpu() to "current->pid != 0".

Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Suggested-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
kernel/rcutiny.c
kernel/rcutree.c