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authorHerbert Xu <herbert@gondor.apana.org.au>2015-06-21 19:11:43 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2015-06-22 15:49:18 +0800
commit7cecadb7cca83953e7857fe9f7273b705cb8ebe7 (patch)
treec799593db728356d1c2485e1d21799a2da1f5c89 /crypto
parent21dbd96f2287a49219d35a0e916cf3f2bcaab9d0 (diff)
downloadlinux-stericsson-7cecadb7cca83953e7857fe9f7273b705cb8ebe7.tar.gz
crypto: rng - Do not free default RNG when it becomes unused
Currently we free the default RNG when its use count hits zero. This was OK when the IV generators would latch onto the RNG at instance creation time and keep it until the instance is torn down. Now that IV generators only keep the RNG reference during init time this scheme causes the default RNG to come and go at a high frequencey. This is highly undesirable as we want to keep a single RNG in use unless the admin wants it to be removed. This patch changes the scheme so that the system RNG once allocated is never removed unless a specifically requested. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/rng.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/crypto/rng.c b/crypto/rng.c
index 13155058b193..b81cffb13bab 100644
--- a/crypto/rng.c
+++ b/crypto/rng.c
@@ -155,14 +155,33 @@ EXPORT_SYMBOL_GPL(crypto_get_default_rng);
void crypto_put_default_rng(void)
{
mutex_lock(&crypto_default_rng_lock);
- if (!--crypto_default_rng_refcnt) {
- crypto_free_rng(crypto_default_rng);
- crypto_default_rng = NULL;
- }
+ crypto_default_rng_refcnt--;
mutex_unlock(&crypto_default_rng_lock);
}
EXPORT_SYMBOL_GPL(crypto_put_default_rng);
+#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
+int crypto_del_default_rng(void)
+{
+ int err = -EBUSY;
+
+ mutex_lock(&crypto_default_rng_lock);
+ if (crypto_default_rng_refcnt)
+ goto out;
+
+ crypto_free_rng(crypto_default_rng);
+ crypto_default_rng = NULL;
+
+ err = 0;
+
+out:
+ mutex_unlock(&crypto_default_rng_lock);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(crypto_del_default_rng);
+#endif
+
int crypto_register_rng(struct rng_alg *alg)
{
struct crypto_alg *base = &alg->base;