diff options
| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-07-31 17:12:48 (GMT) |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-09-23 14:42:49 (GMT) |
| commit | b4270ee356e5ecef5394ab80c0a0301c1676b7f0 (patch) | |
| tree | d600c6dcea20363414220b9b369832af97a8a090 | |
| parent | 1e3fd2b38cea41f5386bf23440f2cbdd74cf13d0 (diff) | |
| download | linux-b4270ee356e5ecef5394ab80c0a0301c1676b7f0.tar.xz | |
rcu: Permit RCU_NONIDLE() to be used from interrupt context
There is a need to use RCU from interrupt context, but either before
rcu_irq_enter() is called or after rcu_irq_exit() is called. If the
interrupt occurs from idle, then lockdep-RCU will complain about such
uses, as they appear to be illegal uses of RCU from the idle loop.
In other environments, RCU_NONIDLE() could be used to properly protect
the use of RCU, but RCU_NONIDLE() currently cannot be invoked except
from process context.
This commit therefore modifies RCU_NONIDLE() to permit its use more
globally.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | include/linux/rcupdate.h | 6 | ||||
| -rw-r--r-- | kernel/rcutiny.c | 2 |
2 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 115ead2..0fbbd52 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -210,14 +210,12 @@ extern void exit_rcu(void); * to nest RCU_NONIDLE() wrappers, but the nesting level is currently * quite limited. If deeper nesting is required, it will be necessary * to adjust DYNTICK_TASK_NESTING_VALUE accordingly. - * - * This macro may be used from process-level code only. */ #define RCU_NONIDLE(a) \ do { \ - rcu_idle_exit(); \ + rcu_irq_enter(); \ do { a; } while (0); \ - rcu_idle_enter(); \ + rcu_irq_exit(); \ } while (0) /* diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index e4163c5..2e073a2 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -115,6 +115,7 @@ void rcu_irq_exit(void) rcu_idle_enter_common(newval); local_irq_restore(flags); } +EXPORT_SYMBOL_GPL(rcu_irq_exit); /* Common code for rcu_idle_exit() and rcu_irq_enter(), see kernel/rcutree.c. */ static void rcu_idle_exit_common(long long oldval) @@ -172,6 +173,7 @@ void rcu_irq_enter(void) rcu_idle_exit_common(oldval); local_irq_restore(flags); } +EXPORT_SYMBOL_GPL(rcu_irq_enter); #ifdef CONFIG_DEBUG_LOCK_ALLOC |