[PATCH v3 14/27] resource: add helpers for fetching rlimits

[Jiri Slaby <jslaby@suse.cz>]

We want to be sure that compiler fetches the limit variable only
once, so add helpers for fetching current and maximal resource
limits which do that.

Add them to sched.h (instead of resource.h) due to circular dependency
 sched.h->resource.h->task_struct
Alternative would be to create a separate res_access.h or similar.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: James Morris <jmorris@namei.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
---
 include/linux/sched.h |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 75e6e60..cf4205b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2574,6 +2574,28 @@ static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
 }
 #endif /* CONFIG_MM_OWNER */
 
+static inline unsigned long task_rlim_get_cur(const struct task_struct *tsk,
+		unsigned int limit)
+{
+	return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_cur);
+}
+
+static inline unsigned long task_rlim_get_max(const struct task_struct *tsk,
+		unsigned int limit)
+{
+	return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_max);
+}
+
+static inline unsigned long rlim_get_cur(unsigned int limit)
+{
+	return task_rlim_get_cur(current, limit);
+}
+
+static inline unsigned long rlim_get_max(unsigned int limit)
+{
+	return task_rlim_get_max(current, limit);
+}
+
 #define TASK_STATE_TO_CHAR_STR "RSDTtZX"
 
 #endif /* __KERNEL__ */
-- 
1.6.5.3