1 files changed, 17 insertions, 1 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7c4e8f1f72d8..941dc0a5a877 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -666,7 +666,7 @@ do {									\
  * your code. (Extra memory is used for special buffers that are
  * allocated when trace_printk() is used.)
  *
- * A little optization trick is done here. If there's only one
+ * A little optimization trick is done here. If there's only one
  * argument, there's no need to scan the string for printf formats.
  * The trace_puts() will suffice. But how can we take advantage of
  * using trace_puts() when trace_printk() has only one argument?
@@ -966,6 +966,22 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
                          "pointer type mismatch in container_of()");    \
         ((type *)(__mptr - offsetof(type, member))); })
 
+/**
+ * container_of_safe - cast a member of a structure out to the containing structure
+ * @ptr:        the pointer to the member.
+ * @type:       the type of the container struct this is embedded in.
+ * @member:     the name of the member within the struct.
+ *
+ * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
+ */
+#define container_of_safe(ptr, type, member) ({                         \
+        void *__mptr = (void *)(ptr);                                   \
+        BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
+                         !__same_type(*(ptr), void),                    \
+                         "pointer type mismatch in container_of()");    \
+        IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) :                     \
+                ((type *)(__mptr - offsetof(type, member))); })
+
 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD