tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/bitops.h>
2#include <linux/kernel.h>
3#include <linux/random.h>
4#include <linux/slab.h>
5#include <linux/types.h>
6
7#include "drm_random.h"
8
9static inline u32 drm_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state)
10{
11 return upper_32_bits((u64)prandom_u32_state(state) * ep_ro);
12}
13
14void drm_random_reorder(unsigned int *order, unsigned int count,
15 struct rnd_state *state)
16{
17 unsigned int i, j;
18
19 for (i = 0; i < count; ++i) {
20 BUILD_BUG_ON(sizeof(unsigned int) > sizeof(u32));
21 j = drm_prandom_u32_max_state(count, state);
22 swap(order[i], order[j]);
23 }
24}
25EXPORT_SYMBOL(drm_random_reorder);
26
27unsigned int *drm_random_order(unsigned int count, struct rnd_state *state)
28{
29 unsigned int *order, i;
30
31 order = kmalloc_array(count, sizeof(*order), GFP_KERNEL);
32 if (!order)
33 return order;
34
35 for (i = 0; i < count; i++)
36 order[i] = i;
37
38 drm_random_reorder(order, count, state);
39 return order;
40}
41EXPORT_SYMBOL(drm_random_order);