random: add get_random_{bytes,u32,u64,int,long,once}_wait family

These functions are simple convenience wrappers that call
wait_for_random_bytes before calling the respective get_random_*
function.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/include/linux/net.h b/include/linux/net.h
index abcfa46a2bd9a6f9eb242dacb199070a05d61014..dda2cc939a531dab67441c6ddf4b7869c6a06159 100644 (file)
--- 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 285f12cb40e6a3d6d21db8fbaca418c133a93d97..9c98aaa87cbcd4f26b8ecdc25b93fae555ab4daa 100644 (file)
--- 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 e29929347c95be46330b54b785a2ebf521cfb093..4aecc339558d5ea1a30e73b8e9889b0cee34f961 100644 (file)
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -58,6 +58,31 @@ static inline unsigned long get_random_long(void)
 #endif
 }
 
+/* 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);