1 files changed, 36 insertions, 22 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 4fa360a13c1e..0d9db2a14f44 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -79,15 +79,6 @@
  */
 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 
-/**
- * FIELD_SIZEOF - get the size of a struct's field
- * @t: the target struct
- * @f: the target struct's field
- * Return: the size of @f in the struct definition without having a
- * declared instance of @t.
- */
-#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
-
 #define typeof_member(T, m)	typeof(((T*)0)->m)
 
 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
@@ -217,7 +208,9 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
  * might_sleep - annotation for functions that can sleep
  *
  * this macro will print a stack trace if it is executed in an atomic
- * context (spinlock, irq-handler, ...).
+ * context (spinlock, irq-handler, ...). Additional sections where blocking is
+ * not allowed can be annotated with non_block_start() and non_block_end()
+ * pairs.
  *
  * This is a useful debugging help to be able to catch problems early and not
  * be bitten later when the calling function happens to sleep when it is not
@@ -233,6 +226,23 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
 # define cant_sleep() \
 	do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
 # define sched_annotate_sleep()	(current->task_state_change = 0)
+/**
+ * non_block_start - annotate the start of section where sleeping is prohibited
+ *
+ * This is on behalf of the oom reaper, specifically when it is calling the mmu
+ * notifiers. The problem is that if the notifier were to block on, for example,
+ * mutex_lock() and if the process which holds that mutex were to perform a
+ * sleeping memory allocation, the oom reaper is now blocked on completion of
+ * that memory allocation. Other blocking calls like wait_event() pose similar
+ * issues.
+ */
+# define non_block_start() (current->non_block_count++)
+/**
+ * non_block_end - annotate the end of section where sleeping is prohibited
+ *
+ * Closes a section opened by non_block_start().
+ */
+# define non_block_end() WARN_ON(current->non_block_count-- == 0)
 #else
   static inline void ___might_sleep(const char *file, int line,
 				   int preempt_offset) { }
@@ -241,6 +251,8 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
 # define might_sleep() do { might_resched(); } while (0)
 # define cant_sleep() do { } while (0)
 # define sched_annotate_sleep() do { } while (0)
+# define non_block_start() do { } while (0)
+# define non_block_end() do { } while (0)
 #endif
 
 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
@@ -307,13 +319,6 @@ extern int oops_may_print(void);
 void do_exit(long error_code) __noreturn;
 void complete_and_exit(struct completion *, long) __noreturn;
 
-#ifdef CONFIG_ARCH_HAS_REFCOUNT
-void refcount_error_report(struct pt_regs *regs, const char *err);
-#else
-static inline void refcount_error_report(struct pt_regs *regs, const char *err)
-{ }
-#endif
-
 /* Internal, do not use. */
 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
@@ -334,8 +339,7 @@ int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
  * @res: Where to write the result of the conversion on success.
  *
  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
+ * Used as a replacement for the simple_strtoull. Return code must be checked.
 */
 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 {
@@ -363,8 +367,7 @@ static inline int __must_check kstrtoul(const char *s, unsigned int base, unsign
  * @res: Where to write the result of the conversion on success.
  *
  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
+ * Used as a replacement for the simple_strtoull. Return code must be checked.
  */
 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 {
@@ -440,7 +443,18 @@ static inline int __must_check kstrtos32_from_user(const char __user *s, size_t
 	return kstrtoint_from_user(s, count, base, res);
 }
 
-/* Obsolete, do not use.  Use kstrto<foo> instead */
+/*
+ * Use kstrto<foo> instead.
+ *
+ * NOTE: simple_strto<foo> does not check for the range overflow and,
+ *	 depending on the input, may give interesting results.
+ *
+ * Use these functions if and only if you cannot use kstrto<foo>, because
+ * the conversion ends on the first non-digit character, which may be far
+ * beyond the supported range. It might be useful to parse the strings like
+ * 10x50 or 12:21 without altering original string or temporary buffer in use.
+ * Keep in mind above caveat.
+ */
 
 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 extern long simple_strtol(const char *,char **,unsigned int);