latent_entropy: Mark functions with __latent_entropy

[mirror_ubuntu-artful-kernel.git] / include / linux / compiler.h

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 436aa4e42221beb16edebd1d5e1bfb3a4fa6af26..ceaddaf76ff1d977834064e3041de588641240f4 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -406,6 +406,10 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
 # define __attribute_const__   /* unimplemented */
 #endif
 
+#ifndef __latent_entropy
+# define __latent_entropy
+#endif
+
 /*
  * Tell gcc if a function is cold. The compiler will assume any path
  * directly leading to the call is unlikely.
@@ -527,13 +531,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
  * object's lifetime is managed by something other than RCU.  That
  * "something other" might be reference counting or simple immortality.
  *
- * The seemingly unused size_t variable is to validate @p is indeed a pointer
- * type by making sure it can be dereferenced.
+ * The seemingly unused variable ___typecheck_p validates that @p is
+ * indeed a pointer type by using a pointer to typeof(*p) as the type.
+ * Taking a pointer to typeof(*p) again is needed in case p is void *.
  */
 #define lockless_dereference(p) \
 ({ \
        typeof(p) _________p1 = READ_ONCE(p); \
-       size_t __maybe_unused __size_of_ptr = sizeof(*(p)); \
+       typeof(*(p)) *___typecheck_p __maybe_unused; \
        smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
        (_________p1); \
 })