[PATCH v4 7/7] s390/crypto: Fix wrong return code to engine in asynch callbacks

[Harald Freudenberger <freude@linux.ibm.com>]

When crypto_finalize_hash_request() or
crypto_finalize_skcipher_request() explicitly completes a request, the
do_one_request callback must return 0 to indicate successful
handling. Returning a negative error code causes the crypto engine to
assume the driver failed to take ownership and triggers a second
completion via crypto_request_complete(), resulting in a double
completion. This pattern occurs in paes_s390.c 4 times and once in
phmac_s390.c.

Fixed in phmac_do_one_request() and all four paes do_one_request
callbacks (ecb, cbc, ctr, xts) by returning 0 after explicit
finalization instead of propagating the error code.

Fixes: 6cd87cb5ef6c ("s390/crypto: Rework protected key AES for true asynch support")
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Cc: stable@vger.kernel.org # 6.16+
---
 arch/s390/crypto/paes_s390.c  | 8 ++++----
 arch/s390/crypto/phmac_s390.c | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/s390/crypto/paes_s390.c b/arch/s390/crypto/paes_s390.c
index 2048327c1ffe..0bc360c7ef15 100644
--- a/arch/s390/crypto/paes_s390.c
+++ b/arch/s390/crypto/paes_s390.c
@@ -574,7 +574,7 @@ static int ecb_paes_do_one_request(struct crypto_engine *engine, void *areq)
 	atomic_dec(&ctx->via_engine_ctr);
 	crypto_finalize_skcipher_request(engine, req, rc);
 	local_bh_enable();
-	return rc;
+	return 0;
 }
 
 static struct skcipher_engine_alg ecb_paes_alg = {
@@ -846,7 +846,7 @@ static int cbc_paes_do_one_request(struct crypto_engine *engine, void *areq)
 	atomic_dec(&ctx->via_engine_ctr);
 	crypto_finalize_skcipher_request(engine, req, rc);
 	local_bh_enable();
-	return rc;
+	return 0;
 }
 
 static struct skcipher_engine_alg cbc_paes_alg = {
@@ -1165,7 +1165,7 @@ static int ctr_paes_do_one_request(struct crypto_engine *engine, void *areq)
 	atomic_dec(&ctx->via_engine_ctr);
 	crypto_finalize_skcipher_request(engine, req, rc);
 	local_bh_enable();
-	return rc;
+	return 0;
 }
 
 static struct skcipher_engine_alg ctr_paes_alg = {
@@ -1618,7 +1618,7 @@ static int xts_paes_do_one_request(struct crypto_engine *engine, void *areq)
 	atomic_dec(&ctx->via_engine_ctr);
 	crypto_finalize_skcipher_request(engine, req, rc);
 	local_bh_enable();
-	return rc;
+	return 0;
 }
 
 static struct skcipher_engine_alg xts_paes_alg = {
diff --git a/arch/s390/crypto/phmac_s390.c b/arch/s390/crypto/phmac_s390.c
index 30c8a59af1a4..89c5fa3dced2 100644
--- a/arch/s390/crypto/phmac_s390.c
+++ b/arch/s390/crypto/phmac_s390.c
@@ -945,7 +945,7 @@ static int phmac_do_one_request(struct crypto_engine *engine, void *areq)
 	atomic_dec(&tfm_ctx->via_engine_ctr);
 	crypto_finalize_hash_request(engine, req, rc);
 	local_bh_enable();
-	return rc;
+	return 0;
 }
 
 #define S390_ASYNC_PHMAC_ALG(x)						\
-- 
2.43.0