mm: add a helper function to check may oom condition

Use helper function to check if we need to deal with oom condition.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/oom.h

@@ -82,6 +82,11 @@ static inline void oom_killer_enable(void)
 	oom_killer_disabled = false;
 }
 
+static inline bool oom_gfp_allowed(gfp_t gfp_mask)
+{
+	return (gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY);
+}
+
 extern struct task_struct *find_lock_task_mm(struct task_struct *p);
 
 /* sysctls */