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 9 static 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 14 void 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 } 25 EXPORT_SYMBOL(drm_random_reorder); 26 27 unsigned 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_TEMPORARY); 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 } 41 EXPORT_SYMBOL(drm_random_order); 42