tls: Fix tls_sw_sendmsg error handling

JIRA: https://issues.redhat.com/browse/RHEL-86020

commit b341ca5
Author: Benjamin Coddington <bcodding@redhat.com>
Date:   Sat Jan 4 10:29:45 2025 -0500

    tls: Fix tls_sw_sendmsg error handling

    We've noticed that NFS can hang when using RPC over TLS on an unstable
    connection, and investigation shows that the RPC layer is stuck in a tight
    loop attempting to transmit, but forever getting -EBADMSG back from the
    underlying network.  The loop begins when tcp_sendmsg_locked() returns
    -EPIPE to tls_tx_records(), but that error is converted to -EBADMSG when
    calling the socket's error reporting handler.

    Instead of converting errors from tcp_sendmsg_locked(), let's pass them
    along in this path.  The RPC layer handles -EPIPE by reconnecting the
    transport, which prevents the endless attempts to transmit on a broken
    connection.

    Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
    Fixes: a42055e ("net/tls: Add support for async encryption of records for performance")
    Link: https://patch.msgid.link/9594185559881679d81f071b181a10eb07cd079f.1736004079.git.bcodding@redhat.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Sabrina Dubroca <sdubroca@redhat.com>

Author: Sabrina Dubroca

net/tls/tls_sw.c

@@ -458,7 +458,7 @@ int tls_tx_records(struct sock *sk, int flags)
 
 tx_err:
 	if (rc < 0 && rc != -EAGAIN)
-		tls_err_abort(sk, -EBADMSG);
+		tls_err_abort(sk, rc);
 
 	return rc;
 }