crypto: api - Add crypto_alg_extsize helper

This patch adds a crypto_alg_extsize helper that can be used
by algorithm types such as pcompress and shash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/algapi.c

@@ -964,6 +964,12 @@ void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
 }
 EXPORT_SYMBOL_GPL(crypto_xor);
 
+unsigned int crypto_alg_extsize(struct crypto_alg *alg)
+{
+	return alg->cra_ctxsize;
+}
+EXPORT_SYMBOL_GPL(crypto_alg_extsize);
+
 static int __init crypto_algapi_init(void)
 {
 	crypto_init_proc();

crypto/internal.h

@@ -103,6 +103,8 @@ int crypto_register_notifier(struct notifier_block *nb);
 int crypto_unregister_notifier(struct notifier_block *nb);
 int crypto_probing_notify(unsigned long val, void *v);
 
+unsigned int crypto_alg_extsize(struct crypto_alg *alg);
+
 static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
 {
 	atomic_inc(&alg->cra_refcnt);