diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-03-15 17:03:43 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-03-16 09:57:49 +0100 |
| commit | e3818b8dce2a934cd1521dbc4827e5238d8f45d8 (patch) | |
| tree | 871d73c67a9bfd84b7ed7c49e9d4027eac7e577f /kernel/rcupdate.c | |
| parent | a3d3203e4bb40f253b1541e310dc0f9305be7c84 (diff) | |
| download | lwn-e3818b8dce2a934cd1521dbc4827e5238d8f45d8.tar.gz lwn-e3818b8dce2a934cd1521dbc4827e5238d8f45d8.zip | |
rcu: Make rcu_read_lock_bh_held() allow for disabled BH
Disabling BH can stand in for rcu_read_lock_bh(), and this patch
updates rcu_read_lock_bh_held() to allow for this. In order to
avoid include-file hell, this function is moved out of line to
kernel/rcupdate.c.
This fixes a false positive RCU warning.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <20100316000343.GA25857@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcupdate.c')
| -rw-r--r-- | kernel/rcupdate.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index f1125c1a6321..63fe25433980 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -45,6 +45,7 @@ #include <linux/mutex.h> #include <linux/module.h> #include <linux/kernel_stat.h> +#include <linux/hardirq.h> #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key rcu_lock_key; @@ -66,6 +67,28 @@ EXPORT_SYMBOL_GPL(rcu_sched_lock_map); int rcu_scheduler_active __read_mostly; EXPORT_SYMBOL_GPL(rcu_scheduler_active); +#ifdef CONFIG_DEBUG_LOCK_ALLOC + +/** + * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section? + * + * Check for bottom half being disabled, which covers both the + * CONFIG_PROVE_RCU and not cases. Note that if someone uses + * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled) + * will show the situation. + * + * Check debug_lockdep_rcu_enabled() to prevent false positives during boot. + */ +int rcu_read_lock_bh_held(void) +{ + if (!debug_lockdep_rcu_enabled()) + return 1; + return in_softirq(); +} +EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); + +#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + /* * This function is invoked towards the end of the scheduler's initialization * process. Before this is called, the idle task might contain |