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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2006-08-06 12:28:44 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2006-09-21 03:16:29 +0200 |
| commit | 6521f30273fbec65146a0f16de74b7b402b0f7b0 (patch) | |
| tree | 1e664f6c1a7c960c60c4cae01585933029f81a5f /crypto | |
| parent | [CRYPTO] api: Rename crypto_alg_get to crypto_mod_get (diff) | |
| download | linux-6521f30273fbec65146a0f16de74b7b402b0f7b0.tar.xz linux-6521f30273fbec65146a0f16de74b7b402b0f7b0.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>
Diffstat (limited to 'crypto')
| -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 8c2743a05f90..5994a58ef954 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 c0a5dd7ce2cc..8543b7a157d6 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: |