crypto: fix broken crypto_register_instance() module handling

Commit 9c521a2 ("crypto: api - remove instance when test failed")
tried to grab a module reference count before the module was even set.

Worse, it then goes on to free the module reference count after it is
set so you quickly end up with a negative module reference count which
prevents people from using any instances belonging to that module.

This patch moves the module initialisation before the reference
count.

Reported-by: Linus Torvalds <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: herbertx

crypto/algapi.c

@@ -525,12 +525,12 @@ int crypto_register_instance(struct crypto_template *tmpl,
 	if (err)
 		return err;
 
-	if (unlikely(!crypto_mod_get(&inst->alg)))
-		return -EAGAIN;
-
 	inst->alg.cra_module = tmpl->module;
 	inst->alg.cra_flags |= CRYPTO_ALG_INSTANCE;
 
+	if (unlikely(!crypto_mod_get(&inst->alg)))
+		return -EAGAIN;
+
 	down_write(&crypto_alg_sem);
 
 	larval = __crypto_register_alg(&inst->alg);