scsi: target: iscsi: Fix login error when receiving

iscsi_target_sk_data_ready() could be invoked indirectly by
iscsi_target_do_login_rx() from the workqueue like this:

iscsi_target_do_login_rx()
  iscsi_target_do_login()
    iscsi_target_do_tx_login_io()
      iscsit_put_login_tx()
        iscsi_login_tx_data()
          tx_data()
            sock_sendmsg_nosec()
              tcp_sendmsg()
                release_sock()
                  sk_backlog_rcv()
                    tcp_v4_do_rcv()
                      tcp_data_ready()
                        iscsi_target_sk_data_ready()

At that time LOGIN_FLAGS_READ_ACTIVE is not cleared and
iscsi_target_sk_data_ready will not read data from the socket. Some iscsi
initiators (libiscsi) will wait forever for a reply.

LOGIN_FLAGS_READ_ACTIVE should be cleared early just after doing the
receive and before writing to the socket in iscsi_target_do_login_rx.

Unfortunately, LOGIN_FLAGS_READ_ACTIVE is also used by sk_state_change to
do login cleanup if a socket was closed at login time. It is supposed to be
cleared after the login PDU is successfully processed and replied.

Introduce another flag, LOGIN_FLAGS_WRITE_ACTIVE, to cover the transmit
part.

Link: https://lore.kernel.org/r/20200716100212.4237-2-houpu@bytedance.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Hou Pu <houpu@bytedance.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index 4fda324f4b35..1eccb2ac7d02 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -556,10 +556,11 @@ struct iscsi_conn {
 	struct socket		*sock;
 	void			(*orig_data_ready)(struct sock *);
 	void			(*orig_state_change)(struct sock *);
-#define LOGIN_FLAGS_READ_ACTIVE		1
-#define LOGIN_FLAGS_CLOSED		2
-#define LOGIN_FLAGS_READY		4
-#define LOGIN_FLAGS_INITIAL_PDU		8
+#define LOGIN_FLAGS_READY		0
+#define LOGIN_FLAGS_INITIAL_PDU		1
+#define LOGIN_FLAGS_READ_ACTIVE		2
+#define LOGIN_FLAGS_WRITE_ACTIVE	3
+#define LOGIN_FLAGS_CLOSED		4
 	unsigned long		login_flags;
 	struct delayed_work	login_work;
 	struct iscsi_login	*login;