@@ -31,7 +31,7 @@ static struct hwrng *current_rng;
/* the current rng has been explicitly chosen by user via sysfs */
static int cur_rng_set_by_user;
static struct task_struct *hwrng_fill;
-/* list of registered rngs, sorted decending by quality */
+/* list of registered rngs */
static LIST_HEAD(rng_list);
/* Protects rng_list and current_rng */
static DEFINE_MUTEX(rng_mutex);
@@ -297,24 +297,28 @@ static struct miscdevice rng_miscdev = {
static int enable_best_rng(void)
{
+ struct hwrng *rng, *new_rng = NULL;
int ret = -ENODEV;
BUG_ON(!mutex_is_locked(&rng_mutex));
- /* rng_list is sorted by quality, use the best (=first) one */
- if (!list_empty(&rng_list)) {
- struct hwrng *new_rng;
-
- new_rng = list_entry(rng_list.next, struct hwrng, list);
- ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng));
- if (!ret)
- cur_rng_set_by_user = 0;
- } else {
+ /* no rng to use? */
+ if (list_empty(&rng_list)) {
drop_current_rng();
cur_rng_set_by_user = 0;
- ret = 0;
+ return 0;
}
+ /* use the rng which offers the best quality */
+ list_for_each_entry(rng, &rng_list, list) {
+ if (!new_rng || rng->quality > new_rng->quality)
+ new_rng = rng;
+ }
+
+ ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng));
+ if (!ret)
+ cur_rng_set_by_user = 0;
+
return ret;
}
@@ -475,7 +479,6 @@ int hwrng_register(struct hwrng *rng)
{
int err = -EINVAL;
struct hwrng *tmp;
- struct list_head *rng_list_ptr;
bool is_new_current = false;
if (!rng->name || (!rng->data_read && !rng->read))
@@ -489,18 +492,11 @@ int hwrng_register(struct hwrng *rng)
if (strcmp(tmp->name, rng->name) == 0)
goto out_unlock;
}
+ list_add_tail(&rng->list, &rng_list);
init_completion(&rng->cleanup_done);
complete(&rng->cleanup_done);
- /* rng_list is sorted by decreasing quality */
- list_for_each(rng_list_ptr, &rng_list) {
- tmp = list_entry(rng_list_ptr, struct hwrng, list);
- if (tmp->quality < rng->quality)
- break;
- }
- list_add_tail(&rng->list, rng_list_ptr);
-
if (!current_rng ||
(!cur_rng_set_by_user && rng->quality > current_rng->quality)) {
/*
There is no real reason why this list needs to be kept ordered by the driver-provided quality value -- a value which is set only by a handful of hw_random devices anyway. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> --- drivers/char/hw_random/core.c | 36 ++++++++++++++++------------------- 1 file changed, 16 insertions(+), 20 deletions(-)