diff options
Diffstat (limited to 'crypto/algapi.c')
| -rw-r--r-- | crypto/algapi.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c index e858946adeed..cd643e294664 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -82,6 +82,15 @@ static void crypto_destroy_instance(struct crypto_alg *alg) crypto_tmpl_put(tmpl); } +/* + * This function adds a spawn to the list secondary_spawns which + * will be used at the end of crypto_remove_spawns to unregister + * instances, unless the spawn happens to be one that is depended + * on by the new algorithm (nalg in crypto_remove_spawns). + * + * This function is also responsible for resurrecting any algorithms + * in the dependency chain of nalg by unsetting n->dead. + */ static struct list_head *crypto_more_spawns(struct crypto_alg *alg, struct list_head *stack, struct list_head *top, @@ -128,6 +137,12 @@ static void crypto_remove_instance(struct crypto_instance *inst, BUG_ON(!list_empty(&inst->alg.cra_users)); } +/* + * Given an algorithm alg, remove all algorithms that depend on it + * through spawns. If nalg is not null, then exempt any algorithms + * that is depended on by nalg. This is useful when nalg itself + * depends on alg. + */ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list, struct crypto_alg *nalg) { @@ -146,6 +161,11 @@ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list, list_move(&spawn->list, &top); } + /* + * Perform a depth-first walk starting from alg through + * the cra_users tree. The list stack records the path + * from alg to the current spawn. + */ spawns = ⊤ do { while (!list_empty(spawns)) { @@ -180,6 +200,11 @@ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list, } while ((spawns = crypto_more_spawns(alg, &stack, &top, &secondary_spawns))); + /* + * Remove all instances that are marked as dead. Also + * complete the resurrection of the others by moving them + * back to the cra_users list. + */ list_for_each_entry_safe(spawn, n, &secondary_spawns, list) { if (!spawn->dead) list_move(&spawn->list, &spawn->alg->cra_users); |