Commit c90e4539 authored by Dominik Brodowski's avatar Dominik Brodowski Committed by Herbert Xu
Browse files

hwrng: core - do not bother to order list of devices by 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: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 973d74e9

drivers/char/hw_random/core.c

+16 −20
Original line number Diff line number Diff line
@@ -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);
@@ -297,23 +297,27 @@ 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;

	/* no rng to use? */

	if (list_empty(&rng_list)) {

		drop_current_rng();

		cur_rng_set_by_user = 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;

	}



		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 {

		drop_current_rng();

		cur_rng_set_by_user = 0;

		ret = 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)) {

		/*