[PATCH 1/2] random: always call random ready function

[Jason A. Donenfeld]

As this interface becomes more heavily used, it will be painful for
callers to always need to check for -EALREADY.

Signed-off-by: Jason A. Donenfeld <ja...@zx2c4.com>
---
 drivers/char/random.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 8ad92707e45f..e161acf35d4a 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1556,40 +1556,45 @@ EXPORT_SYMBOL(wait_for_random_bytes);
 
 /*
  * Add a callback function that will be invoked when the nonblocking
- * pool is initialised.
+ * pool is initialised, or calls that function if it already is.
  *
  * returns: 0 if callback is successfully added
- *         -EALREADY if pool is already initialised (callback not called)
  *         -ENOENT if module for callback is not alive
  */
 int add_random_ready_callback(struct random_ready_callback *rdy)
 {
        struct module *owner;
        unsigned long flags;
-       int err = -EALREADY;
 
-       if (crng_ready())
-               return err;
+       BUG_ON(!rdy->func);
+
+       if (crng_ready()) {
+               rdy->func(rdy);
+               rdy->func = NULL;
+               return 0;
+       }
 
        owner = rdy->owner;
        if (!try_module_get(owner))
                return -ENOENT;
 
        spin_lock_irqsave(&random_ready_list_lock, flags);
-       if (crng_ready())
+       if (crng_ready()) {
+               rdy->func(rdy);
+               rdy->func = NULL;
                goto out;
+       }
 
        owner = NULL;
 
        list_add(&rdy->list, &random_ready_list);
-       err = 0;
 
 out:
        spin_unlock_irqrestore(&random_ready_list_lock, flags);
 
        module_put(owner);
 
-       return err;
+       return 0;
 }
 EXPORT_SYMBOL(add_random_ready_callback);
 
@@ -1601,6 +1606,9 @@ void del_random_ready_callback(struct 
random_ready_callback *rdy)
        unsigned long flags;
        struct module *owner = NULL;
 
+       if (!rdy->func)
+               return;
+
        spin_lock_irqsave(&random_ready_list_lock, flags);
        if (!list_empty(&rdy->list)) {
                list_del_init(&rdy->list);
-- 
2.14.2