[PATCH net 3/5] tls: fix returned read length with async !zc decrypt

We can double-count the chunk size:
 - once via decrypted
 - once in async_copy_bytes, which then becomes part of
   process_rx_list's return value

Subtract it from decrypted before adding in process_rx_list's return
value.

Fixes: 4d42cd6bc2ac ("tls: rx: fix return value for async crypto")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
This logic is so complex, in this series I'm just trying to make all
the selftests pass at the same time :/

 net/tls/tls_sw.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index f23cceaceb36..babbd43d41ed 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c

@@ -2132,7 +2132,13 @@ int tls_sw_recvmsg(struct sock *sk,
 		else
 			err = process_rx_list(ctx, msg, &control, 0,
 					      async_copy_bytes, is_peek);
-		decrypted += max(err, 0);
+
+		if (err > 0) {
+			/* decrypted already accounts for async_copy_bytes,
+			 * we don't want to double-count
+			 */
+			decrypted += err - async_copy_bytes;
+		}
 	}
 
 	copied += decrypted;

-- 
2.40.1