hwrng: core - Reset user selected rng by writing "" to rng_current (142a27f0) · Commits · 戴 / test

drivers/char/hw_random/core.c

+32 −19

Original line number	Diff line number	Diff line
		@@ -292,26 +292,48 @@ static struct miscdevice rng_miscdev = {
		.groups = rng_dev_groups,
		};

		static int enable_best_rng(void)
		{
		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;
		}

		return ret;
		}

		static ssize_t hwrng_attr_current_store(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t len)
		{
		int err;
		int err = -ENODEV;
		struct hwrng *rng;

		err = mutex_lock_interruptible(&rng_mutex);
		if (err)
		return -ERESTARTSYS;
		err = -ENODEV;

		if (sysfs_streq(buf, "")) {
		err = enable_best_rng();
		} else {
		list_for_each_entry(rng, &rng_list, list) {
		if (sysfs_streq(rng->name, buf)) {
		err = 0;
		cur_rng_set_by_user = 1;
		if (rng != current_rng)
		err = set_current_rng(rng);
		break;
		}
		}
		}

		mutex_unlock(&rng_mutex);

		return err ? : len;
		@@ -493,17 +515,8 @@ void hwrng_unregister(struct hwrng *rng)
		mutex_lock(&rng_mutex);

		list_del(&rng->list);
		if (current_rng == rng) {
		drop_current_rng();
		cur_rng_set_by_user = 0;
		/* 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);
		set_current_rng(new_rng);
		}
		}
		if (current_rng == rng)
		enable_best_rng();

		if (list_empty(&rng_list)) {
		mutex_unlock(&rng_mutex);