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authorHerbert Xu <herbert@gondor.apana.org.au>2006-08-06 20:28:44 +1000
committerHerbert Xu <herbert@gondor.apana.org.au>2006-09-21 11:16:29 +1000
commit6521f30273fbec65146a0f16de74b7b402b0f7b0 (patch)
tree1e664f6c1a7c960c60c4cae01585933029f81a5f /crypto
parent72fa491912689ca69dd15f4266945d2c2f2819f8 (diff)
downloadlinux-linaro-stable-6521f30273fbec65146a0f16de74b7b402b0f7b0.tar.gz
[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.c32
-rw-r--r--crypto/proc.c3
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: