[PATCH 5/5] hwrng: core - Move hwrng_init call into set_current_rng

Herbert Xu
2014-12-23T05:40:32Z

We always do hwrng_init in set_current_rng. In fact, our current
reference count system relies on this. So make this explicit by
moving hwrng_init into set_current_rng.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

drivers/char/hw_random/core.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 787ef42..32a8a86 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -71,6 +71,7 @@ MODULE_PARM_DESC(default_quality,
"default entropy content of hwrng per mill");

static void drop_current_rng(void);
+static int hwrng_init(struct hwrng *rng);
static void start_khwrngd(void);

static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
@@ -103,11 +104,20 @@ static inline void cleanup_rng(struct kref *kref)
complete(&rng->cleanup_done);
}

-static void set_current_rng(struct hwrng *rng)
+static int set_current_rng(struct hwrng *rng)
{
+ int err;
+
BUG_ON(!mutex_is_locked(&rng_mutex));
+
+ err = hwrng_init(rng);
+ if (err)
+ return err;
+
drop_current_rng();
current_rng = rng;
+
+ return 0;
}

static void drop_current_rng(void)
@@ -149,7 +159,7 @@ static void put_rng(struct hwrng *rng)
mutex_unlock(&rng_mutex);
}

-static inline int hwrng_init(struct hwrng *rng)
+static int hwrng_init(struct hwrng *rng)
{
if (kref_get_unless_zero(&rng->ref))
goto skip_init;
@@ -310,15 +320,9 @@ static ssize_t hwrng_attr_current_store(struct device *dev,
err = -ENODEV;
list_for_each_entry(rng, &rng_list, list) {
if (strcmp(rng->name, buf) == 0) {
- if (rng == current_rng) {
- err = 0;
- break;
- }
- err = hwrng_init(rng);
- if (err)
- break;
- set_current_rng(rng);
err = 0;
+ if (rng != current_rng)
+ err = set_current_rng(rng);
break;
}
}
@@ -481,10 +485,9 @@ int hwrng_register(struct hwrng *rng)
old_rng = current_rng;
err = 0;
if (!old_rng) {
- err = hwrng_init(rng);
+ err = set_current_rng(rng);
if (err)
goto out_unlock;
- set_current_rng(rng);
}
list_add_tail(&rng->list, &rng_list);

@@ -518,8 +521,7 @@ void hwrng_unregister(struct hwrng *rng)

tail = list_entry(rng_list.prev, struct hwrng, list);

- if (hwrng_init(tail) == 0)
- set_current_rng(tail);
+ set_current_rng(tail);
}
}