3 files changed, 30 insertions, 0 deletions

diff --git a/include/linux/net.h b/include/linux/net.h
index abcfa46a2bd9..dda2cc939a53 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -274,6 +274,8 @@ do {									\
 
 #define net_get_random_once(buf, nbytes)                        \
         get_random_once((buf), (nbytes))
+#define net_get_random_once_wait(buf, nbytes)                   \
+        get_random_once_wait((buf), (nbytes))
 
 int kernel_sendmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
                    size_t num, size_t len);
diff --git a/include/linux/once.h b/include/linux/once.h
index 285f12cb40e6..9c98aaa87cbc 100644
--- a/include/linux/once.h
+++ b/include/linux/once.h
@@ -53,5 +53,7 @@ void __do_once_done(bool *done, struct static_key *once_key,
 
 #define get_random_once(buf, nbytes)                                         \
         DO_ONCE(get_random_bytes, (buf), (nbytes))
+#define get_random_once_wait(buf, nbytes)                                    \
+        DO_ONCE(get_random_bytes_wait, (buf), (nbytes))                      \
 
 #endif /* _LINUX_ONCE_H */
diff --git a/include/linux/random.h b/include/linux/random.h
index 1fa0dc880bd7..eafea6a09361 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -34,6 +34,7 @@ extern void add_input_randomness(unsigned int type, unsigned int code,
 extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
 
 extern void get_random_bytes(void *buf, int nbytes);
+extern int wait_for_random_bytes(void);
 extern int add_random_ready_callback(struct random_ready_callback *rdy);
 extern void del_random_ready_callback(struct random_ready_callback *rdy);
 extern void get_random_bytes_arch(void *buf, int nbytes);
@@ -78,6 +79,31 @@ static inline unsigned long get_random_canary(void)
         return val & CANARY_MASK;
 }
 
+/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
+ * Returns the result of the call to wait_for_random_bytes. */
+static inline int get_random_bytes_wait(void *buf, int nbytes)
+{
+        int ret = wait_for_random_bytes();
+        if (unlikely(ret))
+                return ret;
+        get_random_bytes(buf, nbytes);
+        return 0;
+}
+
+#define declare_get_random_var_wait(var) \
+        static inline int get_random_ ## var ## _wait(var *out) { \
+                int ret = wait_for_random_bytes(); \
+                if (unlikely(ret)) \
+                        return ret; \
+                *out = get_random_ ## var(); \
+                return 0; \
+        }
+declare_get_random_var_wait(u32)
+declare_get_random_var_wait(u64)
+declare_get_random_var_wait(int)
+declare_get_random_var_wait(long)
+#undef declare_get_random_var
+
 unsigned long randomize_page(unsigned long start, unsigned long range);
 
 u32 prandom_u32(void);