diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2006-08-06 20:28:44 +1000 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2006-09-21 11:16:29 +1000 |
| commit | 92534577ae461e4796a211cdc9ee31f7a72206c1 (patch) | |
| tree | b34e248d5e8035550a4fb1d7f95c7c2d5627f7e0 | |
| parent | f5f048c39d5b36dab0e36e1fa6cd87dc128e34fc (diff) | |
| download | linux-crypto-92534577ae461e4796a211cdc9ee31f7a72206c1.tar.gz linux-crypto-92534577ae461e4796a211cdc9ee31f7a72206c1.zip | |
[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 <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | crypto/api.c | 32 | ||||
| -rw-r--r-- | crypto/proc.c | 3 |
2 files changed, 29 insertions, 6 deletions
diff --git a/crypto/api.c b/crypto/api.c index 8c2743a0..5994a58e 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) diff --git a/crypto/proc.c b/crypto/proc.c index c0a5dd7c..8543b7a1 100644 --- a/crypto/proc.c +++ b/crypto/proc.c @@ -12,6 +12,8 @@ * any later version. * */ + +#include <asm/atomic.h> #include <linux/init.h> #include <linux/crypto.h> #include <linux/rwsem.h> @@ -54,6 +56,7 @@ static int c_show(struct seq_file *m, void *p) seq_printf(m, "driver : %s\n", alg->cra_driver_name); seq_printf(m, "module : %s\n", module_name(alg->cra_module)); seq_printf(m, "priority : %d\n", alg->cra_priority); + seq_printf(m, "refcnt : %d\n", atomic_read(&alg->cra_refcnt)); switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) { case CRYPTO_ALG_TYPE_CIPHER: |