iscsi-target: Prepare login code for multi-plexing support

This patch prepares the iscsi-target login code for multi-plexing
support.  This includes:

 - Adding iscsi_tpg_np->tpg_np_kref + iscsit_login_kref_put() for
   handling callback of iscsi_tpg_np->tpg_np_comp
 - Adding kref_put() in iscsit_deaccess_np()
 - Adding kref_put() and wait_for_completion() in
   iscsit_reset_np_thread()
 - Refactor login failure path release logic into
   iscsi_target_login_sess_out()
 - Update __iscsi_target_login_thread() to handle
   iscsi_post_login_handler() asynchronous completion
 - Add shutdown parameter for iscsit_clear_tpg_np_login_thread*()

v3 changes:
 - Convert iscsi_portal_group->np_login_lock to ->np_login_sem
 - Add LOGIN_FLAGS definitions

v2 changes:
 - Remove duplicate call to iscsi_post_login_handler() in
   __iscsi_target_login_thread()
 - Drop unused iscsi_np->np_login_tpg

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

7 files changed, 154 insertions, 107 deletions

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index c4aeac314b2e..1dff3e01f92c 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -220,11 +220,6 @@ int iscsit_access_np(struct iscsi_np *np, struct iscsi_portal_group *tpg)
                 spin_unlock_bh(&np->np_thread_lock);
                 return -1;
         }
-        if (np->np_login_tpg) {
-                pr_err("np->np_login_tpg() is not NULL!\n");
-                spin_unlock_bh(&np->np_thread_lock);
-                return -1;
-        }
         spin_unlock_bh(&np->np_thread_lock);
         /*
          * Determine if the portal group is accepting storage traffic.
@@ -239,26 +234,38 @@ int iscsit_access_np(struct iscsi_np *np, struct iscsi_portal_group *tpg)
         /*
          * Here we serialize access across the TIQN+TPG Tuple.
          */
-        ret = mutex_lock_interruptible(&tpg->np_login_lock);
+        ret = down_interruptible(&tpg->np_login_sem);
         if ((ret != 0) || signal_pending(current))
                 return -1;
 
-        spin_lock_bh(&np->np_thread_lock);
-        np->np_login_tpg = tpg;
-        spin_unlock_bh(&np->np_thread_lock);
+        spin_lock_bh(&tpg->tpg_state_lock);
+        if (tpg->tpg_state != TPG_STATE_ACTIVE) {
+                spin_unlock_bh(&tpg->tpg_state_lock);
+                up(&tpg->np_login_sem);
+                return -1;
+        }
+        spin_unlock_bh(&tpg->tpg_state_lock);
 
         return 0;
 }
 
-int iscsit_deaccess_np(struct iscsi_np *np, struct iscsi_portal_group *tpg)
+void iscsit_login_kref_put(struct kref *kref)
+{
+        struct iscsi_tpg_np *tpg_np = container_of(kref,
+                                struct iscsi_tpg_np, tpg_np_kref);
+
+        complete(&tpg_np->tpg_np_comp);
+}
+
+int iscsit_deaccess_np(struct iscsi_np *np, struct iscsi_portal_group *tpg,
+                       struct iscsi_tpg_np *tpg_np)
 {
         struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
 
-        spin_lock_bh(&np->np_thread_lock);
-        np->np_login_tpg = NULL;
-        spin_unlock_bh(&np->np_thread_lock);
+        up(&tpg->np_login_sem);
 
-        mutex_unlock(&tpg->np_login_lock);
+        if (tpg_np)
+                kref_put(&tpg_np->tpg_np_kref, iscsit_login_kref_put);
 
         if (tiqn)
                 iscsit_put_tiqn_for_login(tiqn);
@@ -410,20 +417,10 @@ struct iscsi_np *iscsit_add_np(
 int iscsit_reset_np_thread(
         struct iscsi_np *np,
         struct iscsi_tpg_np *tpg_np,
-        struct iscsi_portal_group *tpg)
+        struct iscsi_portal_group *tpg,
+        bool shutdown)
 {
         spin_lock_bh(&np->np_thread_lock);
-        if (tpg && tpg_np) {
-                /*
-                 * The reset operation need only be performed when the
-                 * passed struct iscsi_portal_group has a login in progress
-                 * to one of the network portals.
-                 */
-                if (tpg_np->tpg_np->np_login_tpg != tpg) {
-                        spin_unlock_bh(&np->np_thread_lock);
-                        return 0;
-                }
-        }
         if (np->np_thread_state == ISCSI_NP_THREAD_INACTIVE) {
                 spin_unlock_bh(&np->np_thread_lock);
                 return 0;
@@ -438,6 +435,12 @@ int iscsit_reset_np_thread(
         }
         spin_unlock_bh(&np->np_thread_lock);
 
+        if (tpg_np && shutdown) {
+                kref_put(&tpg_np->tpg_np_kref, iscsit_login_kref_put);
+
+                wait_for_completion(&tpg_np->tpg_np_comp);
+        }
+
         return 0;
 }
 
diff --git a/drivers/target/iscsi/iscsi_target.h b/drivers/target/iscsi/iscsi_target.h
index 2c437cb8ca00..f82f6273526e 100644
--- a/drivers/target/iscsi/iscsi_target.h
+++ b/drivers/target/iscsi/iscsi_target.h
@@ -7,13 +7,15 @@ extern void iscsit_put_tiqn_for_login(struct iscsi_tiqn *);
 extern struct iscsi_tiqn *iscsit_add_tiqn(unsigned char *);
 extern void iscsit_del_tiqn(struct iscsi_tiqn *);
 extern int iscsit_access_np(struct iscsi_np *, struct iscsi_portal_group *);
-extern int iscsit_deaccess_np(struct iscsi_np *, struct iscsi_portal_group *);
+extern void iscsit_login_kref_put(struct kref *);
+extern int iscsit_deaccess_np(struct iscsi_np *, struct iscsi_portal_group *,
+                                struct iscsi_tpg_np *);
 extern bool iscsit_check_np_match(struct __kernel_sockaddr_storage *,
                                 struct iscsi_np *, int);
 extern struct iscsi_np *iscsit_add_np(struct __kernel_sockaddr_storage *,
                                 char *, int);
 extern int iscsit_reset_np_thread(struct iscsi_np *, struct iscsi_tpg_np *,
-                                struct iscsi_portal_group *);
+                                struct iscsi_portal_group *, bool);
 extern int iscsit_del_np(struct iscsi_np *);
 extern int iscsit_reject_cmd(struct iscsi_cmd *cmd, u8, unsigned char *);
 extern void iscsit_set_unsoliticed_dataout(struct iscsi_cmd *);
diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 4f77a78edef9..46228465d190 100644
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -554,6 +554,13 @@ struct iscsi_conn {
         struct completion       rx_half_close_comp;
         /* socket used by this connection */
         struct socket           *sock;
+        void                    (*orig_data_ready)(struct sock *, int);
+#define LOGIN_FLAGS_READ_ACTIVE         1
+#define LOGIN_FLAGS_CLOSED              2
+#define LOGIN_FLAGS_READY               4
+        unsigned long           login_flags;
+        struct delayed_work     login_work;
+        struct iscsi_login      *login;
         struct timer_list       nopin_timer;
         struct timer_list       nopin_response_timer;
         struct timer_list       transport_timer;
@@ -584,6 +591,7 @@ struct iscsi_conn {
         void                    *context;
         struct iscsi_login_thread_s *login_thread;
         struct iscsi_portal_group *tpg;
+        struct iscsi_tpg_np     *tpg_np;
         /* Pointer to parent session */
         struct iscsi_session    *sess;
         /* Pointer to thread_set in use for this conn's threads */
@@ -682,6 +690,7 @@ struct iscsi_login {
         u8 version_max;
         u8 login_complete;
         u8 login_failed;
+        bool zero_tsih;
         char isid[6];
         u32 cmd_sn;
         itt_t init_task_tag;
@@ -694,6 +703,7 @@ struct iscsi_login {
         char *req_buf;
         char *rsp_buf;
         struct iscsi_conn *conn;
+        struct iscsi_np *np;
 } ____cacheline_aligned;
 
 struct iscsi_node_attrib {
@@ -773,7 +783,6 @@ struct iscsi_np {
         struct __kernel_sockaddr_storage np_sockaddr;
         struct task_struct      *np_thread;
         struct timer_list       np_login_timer;
-        struct iscsi_portal_group *np_login_tpg;
         void                    *np_context;
         struct iscsit_transport *np_transport;
         struct list_head        np_list;
@@ -788,6 +797,8 @@ struct iscsi_tpg_np {
         struct list_head        tpg_np_parent_list;
         struct se_tpg_np        se_tpg_np;
         spinlock_t              tpg_np_parent_lock;
+        struct completion       tpg_np_comp;
+        struct kref             tpg_np_kref;
 };
 
 struct iscsi_portal_group {
@@ -809,7 +820,7 @@ struct iscsi_portal_group {
         spinlock_t              tpg_state_lock;
         struct se_portal_group tpg_se_tpg;
         struct mutex            tpg_access_lock;
-        struct mutex            np_login_lock;
+        struct semaphore        np_login_sem;
         struct iscsi_tpg_attrib tpg_attrib;
         struct iscsi_node_auth  tpg_demo_auth;
         /* Pointer to default list of iSCSI parameters for TPG */
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 0e85238bdf48..d903c0c702d6 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -50,6 +50,7 @@ static struct iscsi_login *iscsi_login_init_conn(struct iscsi_conn *conn)
                 pr_err("Unable to allocate memory for struct iscsi_login.\n");
                 return NULL;
         }
+        conn->login = login;
         login->conn = conn;
         login->first_request = 1;
 
@@ -684,7 +685,7 @@ static void iscsi_post_login_start_timers(struct iscsi_conn *conn)
                 iscsit_start_nopin_timer(conn);
 }
 
-static int iscsi_post_login_handler(
+int iscsi_post_login_handler(
         struct iscsi_np *np,
         struct iscsi_conn *conn,
         u8 zero_tsih)
@@ -1124,6 +1125,77 @@ iscsit_conn_set_transport(struct iscsi_conn *conn, struct iscsit_transport *t)
         return 0;
 }
 
+void iscsi_target_login_sess_out(struct iscsi_conn *conn,
+                struct iscsi_np *np, bool zero_tsih, bool new_sess)
+{
+        if (new_sess == false)
+                goto old_sess_out;
+
+        pr_err("iSCSI Login negotiation failed.\n");
+        iscsit_collect_login_stats(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
+                                   ISCSI_LOGIN_STATUS_INIT_ERR);
+        if (!zero_tsih || !conn->sess)
+                goto old_sess_out;
+        if (conn->sess->se_sess)
+                transport_free_session(conn->sess->se_sess);
+        if (conn->sess->session_index != 0) {
+                spin_lock_bh(&sess_idr_lock);
+                idr_remove(&sess_idr, conn->sess->session_index);
+                spin_unlock_bh(&sess_idr_lock);
+        }
+        kfree(conn->sess->sess_ops);
+        kfree(conn->sess);
+
+old_sess_out:
+        iscsi_stop_login_thread_timer(np);
+        /*
+         * If login negotiation fails check if the Time2Retain timer
+         * needs to be restarted.
+         */
+        if (!zero_tsih && conn->sess) {
+                spin_lock_bh(&conn->sess->conn_lock);
+                if (conn->sess->session_state == TARG_SESS_STATE_FAILED) {
+                        struct se_portal_group *se_tpg =
+                                        &ISCSI_TPG_C(conn)->tpg_se_tpg;
+
+                        atomic_set(&conn->sess->session_continuation, 0);
+                        spin_unlock_bh(&conn->sess->conn_lock);
+                        spin_lock_bh(&se_tpg->session_lock);
+                        iscsit_start_time2retain_handler(conn->sess);
+                        spin_unlock_bh(&se_tpg->session_lock);
+                } else
+                        spin_unlock_bh(&conn->sess->conn_lock);
+                iscsit_dec_session_usage_count(conn->sess);
+        }
+
+        if (!IS_ERR(conn->conn_rx_hash.tfm))
+                crypto_free_hash(conn->conn_rx_hash.tfm);
+        if (!IS_ERR(conn->conn_tx_hash.tfm))
+                crypto_free_hash(conn->conn_tx_hash.tfm);
+
+        if (conn->conn_cpumask)
+                free_cpumask_var(conn->conn_cpumask);
+
+        kfree(conn->conn_ops);
+
+        if (conn->param_list) {
+                iscsi_release_param_list(conn->param_list);
+                conn->param_list = NULL;
+        }
+        iscsi_target_nego_release(conn);
+
+        if (conn->sock) {
+                sock_release(conn->sock);
+                conn->sock = NULL;
+        }
+
+        if (conn->conn_transport->iscsit_free_conn)
+                conn->conn_transport->iscsit_free_conn(conn);
+
+        iscsit_put_transport(conn->conn_transport);
+        kfree(conn);
+}
+
 static int __iscsi_target_login_thread(struct iscsi_np *np)
 {
         u8 *buffer, zero_tsih = 0;
@@ -1132,6 +1204,8 @@ static int __iscsi_target_login_thread(struct iscsi_np *np)
         struct iscsi_login *login;
         struct iscsi_portal_group *tpg = NULL;
         struct iscsi_login_req *pdu;
+        struct iscsi_tpg_np *tpg_np;
+        bool new_sess = false;
 
         flush_signals(current);
 
@@ -1273,6 +1347,7 @@ static int __iscsi_target_login_thread(struct iscsi_np *np)
                 tpg = conn->tpg;
                 goto new_sess_out;
         }
+        login->zero_tsih = zero_tsih;
 
         tpg = conn->tpg;
         if (!tpg) {
@@ -1288,7 +1363,8 @@ static int __iscsi_target_login_thread(struct iscsi_np *np)
                         goto old_sess_out;
         }
 
-        if (iscsi_target_start_negotiation(login, conn) < 0)
+        ret = iscsi_target_start_negotiation(login, conn);
+        if (ret < 0)
                 goto new_sess_out;
 
         if (!conn->sess) {
@@ -1301,84 +1377,32 @@ static int __iscsi_target_login_thread(struct iscsi_np *np)
         if (signal_pending(current))
                 goto new_sess_out;
 
-        ret = iscsi_post_login_handler(np, conn, zero_tsih);
+        if (ret == 1) {
+                tpg_np = conn->tpg_np;
 
-        if (ret < 0)
-                goto new_sess_out;
+                ret = iscsi_post_login_handler(np, conn, zero_tsih);
+                if (ret < 0)
+                        goto new_sess_out;
+
+                iscsit_deaccess_np(np, tpg, tpg_np);
+        }
 
-        iscsit_deaccess_np(np, tpg);
         tpg = NULL;
+        tpg_np = NULL;
         /* Get another socket */
         return 1;
 
 new_sess_out:
-        pr_err("iSCSI Login negotiation failed.\n");
-        iscsit_collect_login_stats(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
-                                  ISCSI_LOGIN_STATUS_INIT_ERR);
-        if (!zero_tsih || !conn->sess)
-                goto old_sess_out;
-        if (conn->sess->se_sess)
-                transport_free_session(conn->sess->se_sess);
-        if (conn->sess->session_index != 0) {
-                spin_lock_bh(&sess_idr_lock);
-                idr_remove(&sess_idr, conn->sess->session_index);
-                spin_unlock_bh(&sess_idr_lock);
-        }
-        kfree(conn->sess->sess_ops);
-        kfree(conn->sess);
+        new_sess = true;
 old_sess_out:
-        iscsi_stop_login_thread_timer(np);
-        /*
-         * If login negotiation fails check if the Time2Retain timer
-         * needs to be restarted.
-         */
-        if (!zero_tsih && conn->sess) {
-                spin_lock_bh(&conn->sess->conn_lock);
-                if (conn->sess->session_state == TARG_SESS_STATE_FAILED) {
-                        struct se_portal_group *se_tpg =
-                                        &ISCSI_TPG_C(conn)->tpg_se_tpg;
-
-                        atomic_set(&conn->sess->session_continuation, 0);
-                        spin_unlock_bh(&conn->sess->conn_lock);
-                        spin_lock_bh(&se_tpg->session_lock);
-                        iscsit_start_time2retain_handler(conn->sess);
-                        spin_unlock_bh(&se_tpg->session_lock);
-                } else
-                        spin_unlock_bh(&conn->sess->conn_lock);
-                iscsit_dec_session_usage_count(conn->sess);
-        }
-
-        if (!IS_ERR(conn->conn_rx_hash.tfm))
-                crypto_free_hash(conn->conn_rx_hash.tfm);
-        if (!IS_ERR(conn->conn_tx_hash.tfm))
-                crypto_free_hash(conn->conn_tx_hash.tfm);
-
-        if (conn->conn_cpumask)
-                free_cpumask_var(conn->conn_cpumask);
-
-        kfree(conn->conn_ops);
-
-        if (conn->param_list) {
-                iscsi_release_param_list(conn->param_list);
-                conn->param_list = NULL;
-        }
-        iscsi_target_nego_release(conn);
-
-        if (conn->sock) {
-                sock_release(conn->sock);
-                conn->sock = NULL;
-        }
-
-        if (conn->conn_transport->iscsit_free_conn)
-                conn->conn_transport->iscsit_free_conn(conn);
-
-        iscsit_put_transport(conn->conn_transport);
-
-        kfree(conn);
+        tpg_np = conn->tpg_np;
+        iscsi_target_login_sess_out(conn, np, zero_tsih, new_sess);
+        new_sess = false;
 
         if (tpg) {
-                iscsit_deaccess_np(np, tpg);
+                iscsit_deaccess_np(np, tpg, tpg_np);
                 tpg = NULL;
+                tpg_np = NULL;
         }
 
 out:
diff --git a/drivers/target/iscsi/iscsi_target_login.h b/drivers/target/iscsi/iscsi_target_login.h
index 63efd2878451..29d098324b7f 100644
--- a/drivers/target/iscsi/iscsi_target_login.h
+++ b/drivers/target/iscsi/iscsi_target_login.h
@@ -12,6 +12,9 @@ extern int iscsit_accept_np(struct iscsi_np *, struct iscsi_conn *);
 extern int iscsit_get_login_rx(struct iscsi_conn *, struct iscsi_login *);
 extern int iscsit_put_login_tx(struct iscsi_conn *, struct iscsi_login *, u32);
 extern void iscsit_free_conn(struct iscsi_np *, struct iscsi_conn *);
+extern int iscsi_post_login_handler(struct iscsi_np *, struct iscsi_conn *, u8);
+extern void iscsi_target_login_sess_out(struct iscsi_conn *, struct iscsi_np *,
+                                bool, bool);
 extern int iscsi_target_login_thread(void *);
 extern int iscsi_login_disable_FIM_keys(struct iscsi_param_list *, struct iscsi_conn *);
 
diff --git a/drivers/target/iscsi/iscsi_target_tpg.c b/drivers/target/iscsi/iscsi_target_tpg.c
index 439260b7d87f..4bf8913992a5 100644
--- a/drivers/target/iscsi/iscsi_target_tpg.c
+++ b/drivers/target/iscsi/iscsi_target_tpg.c
@@ -49,7 +49,7 @@ struct iscsi_portal_group *iscsit_alloc_portal_group(struct iscsi_tiqn *tiqn, u1
         INIT_LIST_HEAD(&tpg->tpg_gnp_list);
         INIT_LIST_HEAD(&tpg->tpg_list);
         mutex_init(&tpg->tpg_access_lock);
-        mutex_init(&tpg->np_login_lock);
+        sema_init(&tpg->np_login_sem, 1);
         spin_lock_init(&tpg->tpg_state_lock);
         spin_lock_init(&tpg->tpg_np_lock);
 
@@ -175,18 +175,20 @@ void iscsit_put_tpg(struct iscsi_portal_group *tpg)
 
 static void iscsit_clear_tpg_np_login_thread(
         struct iscsi_tpg_np *tpg_np,
-        struct iscsi_portal_group *tpg)
+        struct iscsi_portal_group *tpg,
+        bool shutdown)
 {
         if (!tpg_np->tpg_np) {
                 pr_err("struct iscsi_tpg_np->tpg_np is NULL!\n");
                 return;
         }
 
-        iscsit_reset_np_thread(tpg_np->tpg_np, tpg_np, tpg);
+        iscsit_reset_np_thread(tpg_np->tpg_np, tpg_np, tpg, shutdown);
 }
 
 void iscsit_clear_tpg_np_login_threads(
-        struct iscsi_portal_group *tpg)
+        struct iscsi_portal_group *tpg,
+        bool shutdown)
 {
         struct iscsi_tpg_np *tpg_np;
 
@@ -197,7 +199,7 @@ void iscsit_clear_tpg_np_login_threads(
                         continue;
                 }
                 spin_unlock(&tpg->tpg_np_lock);
-                iscsit_clear_tpg_np_login_thread(tpg_np, tpg);
+                iscsit_clear_tpg_np_login_thread(tpg_np, tpg, shutdown);
                 spin_lock(&tpg->tpg_np_lock);
         }
         spin_unlock(&tpg->tpg_np_lock);
@@ -268,6 +270,8 @@ int iscsit_tpg_del_portal_group(
         tpg->tpg_state = TPG_STATE_INACTIVE;
         spin_unlock(&tpg->tpg_state_lock);
 
+        iscsit_clear_tpg_np_login_threads(tpg, true);
+
         if (iscsit_release_sessions_for_tpg(tpg, force) < 0) {
                 pr_err("Unable to delete iSCSI Target Portal Group:"
                         " %hu while active sessions exist, and force=0\n",
@@ -368,7 +372,7 @@ int iscsit_tpg_disable_portal_group(struct iscsi_portal_group *tpg, int force)
         tpg->tpg_state = TPG_STATE_INACTIVE;
         spin_unlock(&tpg->tpg_state_lock);
 
-        iscsit_clear_tpg_np_login_threads(tpg);
+        iscsit_clear_tpg_np_login_threads(tpg, false);
 
         if (iscsit_release_sessions_for_tpg(tpg, force) < 0) {
                 spin_lock(&tpg->tpg_state_lock);
@@ -520,7 +524,7 @@ static int iscsit_tpg_release_np(
         struct iscsi_portal_group *tpg,
         struct iscsi_np *np)
 {
-        iscsit_clear_tpg_np_login_thread(tpg_np, tpg);
+        iscsit_clear_tpg_np_login_thread(tpg_np, tpg, true);
 
         pr_debug("CORE[%s] - Removed Network Portal: %s:%hu,%hu on %s\n",
                 tpg->tpg_tiqn->tiqn, np->np_ip, np->np_port, tpg->tpgt,
diff --git a/drivers/target/iscsi/iscsi_target_tpg.h b/drivers/target/iscsi/iscsi_target_tpg.h
index dda48c141a8c..60ef4a9ad91b 100644
--- a/drivers/target/iscsi/iscsi_target_tpg.h
+++ b/drivers/target/iscsi/iscsi_target_tpg.h
@@ -8,7 +8,7 @@ extern struct iscsi_portal_group *iscsit_get_tpg_from_np(struct iscsi_tiqn *,
                         struct iscsi_np *);
 extern int iscsit_get_tpg(struct iscsi_portal_group *);
 extern void iscsit_put_tpg(struct iscsi_portal_group *);
-extern void iscsit_clear_tpg_np_login_threads(struct iscsi_portal_group *);
+extern void iscsit_clear_tpg_np_login_threads(struct iscsi_portal_group *, bool);
 extern void iscsit_tpg_dump_params(struct iscsi_portal_group *);
 extern int iscsit_tpg_add_portal_group(struct iscsi_tiqn *, struct iscsi_portal_group *);
 extern int iscsit_tpg_del_portal_group(struct iscsi_tiqn *, struct iscsi_portal_group *,