From 6521f30273fbec65146a0f16de74b7b402b0f7b0 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 6 Aug 2006 20:28:44 +1000 Subject: [CRYPTO] api: Add crypto_alg reference counting Up until now we've relied on module reference counting to ensure that the crypto_alg structures don't disappear from under us. This was good enough as long as each crypto_alg came from exactly one module. However, with parameterised crypto algorithms a crypto_alg object may need two or more modules to operate. This means that we need to count the references to the crypto_alg object directly. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- crypto/api.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) (limited to 'crypto/api.c') diff --git a/crypto/api.c b/crypto/api.c index 8c2743a05f9..5994a58ef95 100644 --- a/crypto/api.c +++ b/crypto/api.c @@ -29,13 +29,26 @@ LIST_HEAD(crypto_alg_list); DECLARE_RWSEM(crypto_alg_sem); -static inline int crypto_mod_get(struct crypto_alg *alg) +static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg) { - return try_module_get(alg->cra_module); + atomic_inc(&alg->cra_refcnt); + return alg; +} + +static inline void crypto_alg_put(struct crypto_alg *alg) +{ + if (atomic_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy) + alg->cra_destroy(alg); +} + +static struct crypto_alg *crypto_mod_get(struct crypto_alg *alg) +{ + return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL; } -static inline void crypto_mod_put(struct crypto_alg *alg) +static void crypto_mod_put(struct crypto_alg *alg) { + crypto_alg_put(alg); module_put(alg->cra_module); } @@ -274,6 +287,7 @@ int crypto_register_alg(struct crypto_alg *alg) } list_add(&alg->cra_list, &crypto_alg_list); + atomic_set(&alg->cra_refcnt, 1); out: up_write(&crypto_alg_sem); return ret; @@ -284,8 +298,6 @@ int crypto_unregister_alg(struct crypto_alg *alg) int ret = -ENOENT; struct crypto_alg *q; - BUG_ON(!alg->cra_module); - down_write(&crypto_alg_sem); list_for_each_entry(q, &crypto_alg_list, cra_list) { if (alg == q) { @@ -296,7 +308,15 @@ int crypto_unregister_alg(struct crypto_alg *alg) } out: up_write(&crypto_alg_sem); - return ret; + + if (ret) + return ret; + + BUG_ON(atomic_read(&alg->cra_refcnt) != 1); + if (alg->cra_destroy) + alg->cra_destroy(alg); + + return 0; } int crypto_alg_available(const char *name, u32 flags) -- cgit v1.2.3