crypto: api - Move type exit function into crypto_tfm

The type exit function needs to undo any allocations done by the type
init function.  However, the type init function may differ depending
on the upper-level type of the transform (e.g., a crypto_blkcipher
instantiated as a crypto_ablkcipher).

So we need to move the exit function out of the lower-level
structure and into crypto_tfm itself.

As it stands this is a no-op since nobody uses exit functions at
all.  However, all cases where a lower-level type is instantiated
as a different upper-level type (such as blkcipher as ablkcipher)
will be converted such that they allocate the underlying transform
and use that instead of casting (e.g., crypto_ablkcipher casted
into crypto_blkcipher).  That will need to use a different exit
function depending on the upper-level type.

This patch also allows the type init/exit functions to call (or not)
cra_init/cra_exit instead of always calling them from the top level.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/api.c

@@ -300,8 +300,8 @@ static void crypto_exit_ops(struct crypto_tfm *tfm)
 	const struct crypto_type *type = tfm->__crt_alg->cra_type;
 
 	if (type) {
-		if (type->exit)
-			type->exit(tfm);
+		if (tfm->exit)
+			tfm->exit(tfm);
 		return;
 	}
 
@@ -379,17 +379,16 @@ struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 	if (err)
 		goto out_free_tfm;
 
-	if (alg->cra_init && (err = alg->cra_init(tfm))) {
-		if (err == -EAGAIN)
-			crypto_shoot_alg(alg);
+	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 		goto cra_init_failed;
-	}
 
 	goto out;
 
 cra_init_failed:
 	crypto_exit_ops(tfm);
 out_free_tfm:
+	if (err == -EAGAIN)
+		crypto_shoot_alg(alg);
 	kfree(tfm);
 out_err:
 	tfm = ERR_PTR(err);
@@ -469,7 +468,7 @@ void crypto_free_tfm(struct crypto_tfm *tfm)
 	alg = tfm->__crt_alg;
 	size = sizeof(*tfm) + alg->cra_ctxsize;
 
-	if (alg->cra_exit)
+	if (!tfm->exit && alg->cra_exit)
 		alg->cra_exit(tfm);
 	crypto_exit_ops(tfm);
 	crypto_mod_put(alg);

include/crypto/algapi.h

@@ -23,7 +23,6 @@ struct seq_file;
 struct crypto_type {
 	unsigned int (*ctxsize)(struct crypto_alg *alg, u32 type, u32 mask);
 	int (*init)(struct crypto_tfm *tfm, u32 type, u32 mask);
-	void (*exit)(struct crypto_tfm *tfm);
 	void (*show)(struct seq_file *m, struct crypto_alg *alg);
 };
 

include/linux/crypto.h

@@ -481,6 +481,8 @@ struct crypto_tfm {
 		struct rng_tfm rng;
 	} crt_u;
 
+	void (*exit)(struct crypto_tfm *tfm);
+	
 	struct crypto_alg *__crt_alg;
 
 	void *__crt_ctx[] CRYPTO_MINALIGN_ATTR;