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

* [PATCH 1/2] random: always call random ready function
       [not found] <CAHmME9qwoSwFi7fsg1Z+gcEh1fBY+KY2rJ81UTHYn2ZMcjjwFA@mail.gmail.com>
@ 2017-10-19 20:45 ` Jason A. Donenfeld
  2017-10-19 20:45   ` [PATCH 2/2] crypto/drbg: account for no longer returning -EALREADY Jason A. Donenfeld
                     ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Jason A. Donenfeld @ 2017-10-19 20:45 UTC (permalink / raw)
  To: Kees Cook, LKML, linux-crypto, herbert, tytso, gregkh; +Cc: 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 <Jason@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

^ permalink raw reply related	[flat|nested] 6+ messages in thread