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Merge branches 'slab/for-6.5/prandom', 'slab/for-6.5/slab_no_merge' and 'slab/for-6.5/slab-deprecate' into slab/for-next

Browse source 
Merge the feature branches scheduled for 6.5:

- replace the usage of weak PRNGs, by David Keisar Schmidt

- introduce the SLAB_NO_MERGE kmem_cache flag, by Jesper Dangaard Brouer

- deprecate CONFIG_SLAB, with a planned removal, by myself
This commit is contained in:
Vlastimil Babka 2023-06-16 11:05:59 +02:00
commit 7bc162d5cc
141 changed files with 51 additions and 178 deletions
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29
mm/slab.c
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@ -2355,44 +2355,34 @@ static void cache_init_objs_debug(struct kmem_cache *cachep, struct slab *slab)
#ifdef CONFIG_SLAB_FREELIST_RANDOM
/* Hold information during a freelist initialization */
union freelist_init_state {
struct {
unsigned int pos;
unsigned int *list;
unsigned int count;
};
struct rnd_state rnd_state;
struct freelist_init_state {
unsigned int pos;
unsigned int *list;
unsigned int count;
};
/*
* Initialize the state based on the randomization method available.
* return true if the pre-computed list is available, false otherwise.
*/
static bool freelist_state_initialize(union freelist_init_state *state,
static bool freelist_state_initialize(struct freelist_init_state *state,
struct kmem_cache *cachep,
unsigned int count)
{
bool ret;
unsigned int rand;
/* Use best entropy available to define a random shift */
rand = get_random_u32();
/* Use a random state if the pre-computed list is not available */
if (!cachep->random_seq) {
prandom_seed_state(&state->rnd_state, rand);
ret = false;
} else {
state->list = cachep->random_seq;
state->count = count;
state->pos = rand % count;
state->pos = get_random_u32_below(count);
ret = true;
}
return ret;
}
/* Get the next entry on the list and randomize it using a random shift */
static freelist_idx_t next_random_slot(union freelist_init_state *state)
static freelist_idx_t next_random_slot(struct freelist_init_state *state)
{
if (state->pos >= state->count)
state->pos = 0;
@ -2413,7 +2403,7 @@ static void swap_free_obj(struct slab *slab, unsigned int a, unsigned int b)
static bool shuffle_freelist(struct kmem_cache *cachep, struct slab *slab)
{
unsigned int objfreelist = 0, i, rand, count = cachep->num;
union freelist_init_state state;
struct freelist_init_state state;
bool precomputed;
if (count < 2)
@ -2442,8 +2432,7 @@ static bool shuffle_freelist(struct kmem_cache *cachep, struct slab *slab)
/* Fisher-Yates shuffle */
for (i = count - 1; i > 0; i--) {
rand = prandom_u32_state(&state.rnd_state);
rand %= (i + 1);
rand = get_random_u32_below(i + 1);
swap_free_obj(slab, i, rand);
}
} else {