padata: make padata_do_parallel to return zero on success

To return -EINPROGRESS on success in padata_do_parallel was
considered to be odd. This patch changes this to return zero
on success. Also the only user of padata, pcrypt is adapted to
convert a return of zero to -EINPROGRESS within the crypto layer.
This also removes the pcrypt fallback if padata_do_parallel
was called on a not running padata instance as we can't handle it
anymore. This fallback was unused, so it's save to remove it.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/pcrypt.c

@@ -143,10 +143,8 @@ static int pcrypt_aead_encrypt(struct aead_request *req)
 	aead_request_set_assoc(creq, req->assoc, req->assoclen);
 
 	err = pcrypt_do_parallel(padata, &ctx->cb_cpu, pcrypt_enc_padata);
-	if (err)
-		return err;
-	else
-		err = crypto_aead_encrypt(creq);
+	if (!err)
+		return -EINPROGRESS;
 
 	return err;
 }
@@ -187,10 +185,8 @@ static int pcrypt_aead_decrypt(struct aead_request *req)
 	aead_request_set_assoc(creq, req->assoc, req->assoclen);
 
 	err = pcrypt_do_parallel(padata, &ctx->cb_cpu, pcrypt_dec_padata);
-	if (err)
-		return err;
-	else
-		err = crypto_aead_decrypt(creq);
+	if (!err)
+		return -EINPROGRESS;
 
 	return err;
 }
@@ -233,10 +229,8 @@ static int pcrypt_aead_givencrypt(struct aead_givcrypt_request *req)
 	aead_givcrypt_set_giv(creq, req->giv, req->seq);
 
 	err = pcrypt_do_parallel(padata, &ctx->cb_cpu, pcrypt_enc_padata);
-	if (err)
-		return err;
-	else
-		err = crypto_aead_givencrypt(creq);
+	if (!err)
+		return -EINPROGRESS;
 
 	return err;
 }

kernel/padata.c

@@ -111,10 +111,13 @@ int padata_do_parallel(struct padata_instance *pinst,
 
 	pd = rcu_dereference(pinst->pd);
 
-	err = 0;
+	err = -EINVAL;
 	if (!(pinst->flags & PADATA_INIT))
 		goto out;
 
+	if (!cpumask_test_cpu(cb_cpu, pd->cpumask))
+		goto out;
+
 	err =  -EBUSY;
 	if ((pinst->flags & PADATA_RESET))
 		goto out;
@@ -122,11 +125,7 @@ int padata_do_parallel(struct padata_instance *pinst,
 	if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
 		goto out;
 
-	err = -EINVAL;
-	if (!cpumask_test_cpu(cb_cpu, pd->cpumask))
-		goto out;
-
-	err = -EINPROGRESS;
+	err = 0;
 	atomic_inc(&pd->refcnt);
 	padata->pd = pd;
 	padata->cb_cpu = cb_cpu;