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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>
This commit is contained in:
Hou Pu 2020-07-16 06:02:11 -04:00 committed by Martin K. Petersen
parent 6eaa862747
commit 4e108d4f28
2 changed files with 35 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/target/iscsi/iscsi_target_nego.c
View File

@ -625,13 +625,37 @@ static void iscsi_target_do_login_rx(struct work_struct *work)
pr_debug("iscsi_target_do_login_rx after rx_login_io, %p, %s:%d\n",
conn, current->comm, current->pid);
/*
* LOGIN_FLAGS_READ_ACTIVE is cleared so that sk_data_ready
* could be triggered again after this.
*
* LOGIN_FLAGS_WRITE_ACTIVE is cleared after we successfully
* process a login PDU, so that sk_state_chage can do login
* cleanup as needed if the socket is closed. If a delayed work is
* ongoing (LOGIN_FLAGS_WRITE_ACTIVE or LOGIN_FLAGS_READ_ACTIVE),
* sk_state_change will leave the cleanup to the delayed work or
* it will schedule a delayed work to do cleanup.
*/
if (conn->sock) {
struct sock *sk = conn->sock->sk;
write_lock_bh(&sk->sk_callback_lock);
if (!test_bit(LOGIN_FLAGS_INITIAL_PDU, &conn->login_flags)) {
clear_bit(LOGIN_FLAGS_READ_ACTIVE, &conn->login_flags);
set_bit(LOGIN_FLAGS_WRITE_ACTIVE, &conn->login_flags);
}
write_unlock_bh(&sk->sk_callback_lock);
}
rc = iscsi_target_do_login(conn, login);
if (rc < 0) {
goto err;
} else if (!rc) {
if (iscsi_target_sk_check_and_clear(conn, LOGIN_FLAGS_READ_ACTIVE))
if (iscsi_target_sk_check_and_clear(conn,
LOGIN_FLAGS_WRITE_ACTIVE))
goto err;
} else if (rc == 1) {
cancel_delayed_work(&conn->login_work);
iscsi_target_nego_release(conn);
iscsi_post_login_handler(np, conn, zero_tsih);
iscsit_deaccess_np(np, tpg, tpg_np);
@ -640,6 +664,7 @@ static void iscsi_target_do_login_rx(struct work_struct *work)
err:
iscsi_target_restore_sock_callbacks(conn);
cancel_delayed_work(&conn->login_work);
iscsi_target_login_drop(conn, login);
iscsit_deaccess_np(np, tpg, tpg_np);
}
@ -670,9 +695,10 @@ static void iscsi_target_sk_state_change(struct sock *sk)
state = __iscsi_target_sk_check_close(sk);
pr_debug("__iscsi_target_sk_close_change: state: %d\n", state);
if (test_bit(LOGIN_FLAGS_READ_ACTIVE, &conn->login_flags)) {
pr_debug("Got LOGIN_FLAGS_READ_ACTIVE=1 sk_state_change"
" conn: %p\n", conn);
if (test_bit(LOGIN_FLAGS_READ_ACTIVE, &conn->login_flags) ||
test_bit(LOGIN_FLAGS_WRITE_ACTIVE, &conn->login_flags)) {
pr_debug("Got LOGIN_FLAGS_{READ|WRITE}_ACTIVE=1"
" sk_state_change conn: %p\n", conn);
if (state)
set_bit(LOGIN_FLAGS_CLOSED, &conn->login_flags);
write_unlock_bh(&sk->sk_callback_lock);

9
include/target/iscsi/iscsi_target_core.h
View File

@ -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;