This is needed so that callers would not get 'context imbalance' warnings from the sparse tool.
As a side effect, this patch fixes the following sparse warnings:
CHECK mm/oom_kill.c mm/oom_kill.c:201:28: warning: context imbalance in 'oom_badness' - unexpected unlock include/linux/rcupdate.h:249:30: warning: context imbalance in 'dump_tasks' - unexpected unlock mm/oom_kill.c:453:9: warning: context imbalance in 'oom_kill_task' - unexpected unlock CHECK mm/memcontrol.c ... mm/memcontrol.c:1130:17: warning: context imbalance in 'task_in_mem_cgroup' - unexpected unlock
Signed-off-by: Anton Vorontsov anton.vorontsov@linaro.org ---
On Mon, Feb 06, 2012 at 04:27:32PM -0500, KOSAKI Motohiro wrote: [...]
Unfortunately this isn't possible in this case. Unlike '({})' GCC extension, do-while statement does not evaluate to a value, i.e. 'x = do { 123; } while (0);' is illegal.
Ah, you are right, my bad, sorry about that.
greg k-h
Some __cond_lock() caller are inline functions. Is this bad?
No, that's great, actually. :-) Not obvious, but seems like sparse understands __cond_lock in inline functions, so I'd better use it.
Thanks,
include/linux/oom.h | 12 +++++++++++- mm/oom_kill.c | 2 +- 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/include/linux/oom.h b/include/linux/oom.h index 552fba9..7c8946a 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -21,6 +21,7 @@
#ifdef __KERNEL__
+#include <linux/compiler.h> #include <linux/sched.h> #include <linux/types.h> #include <linux/nodemask.h> @@ -65,7 +66,16 @@ static inline void oom_killer_enable(void) oom_killer_disabled = false; }
-extern struct task_struct *find_lock_task_mm(struct task_struct *p); +extern struct task_struct *__find_lock_task_mm(struct task_struct *p); + +static inline struct task_struct *find_lock_task_mm(struct task_struct *p) +{ + struct task_struct *ret; + + ret = __find_lock_task_mm(p); + (void)__cond_lock(&p->alloc_lock, ret); + return ret; +}
/* sysctls */ extern int sysctl_oom_dump_tasks; diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 2958fd8..0ebb383 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -136,7 +136,7 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk, * pointer. Return p, or any of its subthreads with a valid ->mm, with * task_lock() held. */ -struct task_struct *find_lock_task_mm(struct task_struct *p) +struct task_struct *__find_lock_task_mm(struct task_struct *p) { struct task_struct *t = p;