Re: [PATCH 1/3] Make /dev/urandom scalable

[Rasmus Villemoes <linux@rasmusvillemoes.dk>]

On Thu, Sep 24 2015, Andi Kleen <andi@firstfloor.org> wrote:

>
> v2: Fix name of pool 0. Fix race with interrupts. Make
> iteration loops slightly more efficient. Add ifdefs to avoid
> any extra code on non-NUMA. Delay other pool use to when
> the original pool initialized and initialize the pools from
> pool 0. Add comments on memory allocation.

More bikeshedding. Please ignore unless you do a v3 anyway.

>  static struct entropy_store nonblocking_pool = {
>  	.poolinfo = &poolinfo_table[1],
> -	.name = "nonblocking",
> +	.name = "nonblocking pool 0",

Hm, yeah, but then you should probably also update the blocking pool's
name (or use the format "nonblocking %d").

> +#define POOL_INIT_BYTES (128 / 8)
> +
> +void init_node_pools(void)
> +{
> +#ifdef CONFIG_NUMA
> +	int i;
> +	for (i = 0; i < num_possible_nodes(); i++) {

int num_nodes = num_possible_nodes();
for (i = 0; i < num_nodes; i++) {

>  static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
>  {
> +	int i;
>  	int size, ent_count;
>  	int __user *p = (int __user *)arg;
>  	int retval;
> +	struct entropy_store *pool;
>  
>  	switch (cmd) {
>  	case RNDGETENTCNT:
> @@ -1569,6 +1696,10 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
>  			return -EPERM;
>  		input_pool.entropy_count = 0;
>  		nonblocking_pool.entropy_count = 0;
> +		if (nonblocking_node_pool)
> +			for_each_nb_pool (i, pool) {
> +				pool->entropy_count = 0;
> +			} end_for_each_nb();

extra ;. harmless in this case, but could cause slightly hard-to-understand build
failures if that if grows an else.

Rasmus