iscsi-target: Convert iscsi_thread_set usage to kthread.h

This patch converts iscsi-target code to use modern kthread.h API
callers for creating RX/TX threads for each new iscsi_conn descriptor,
and releasing associated RX/TX threads during connection shutdown.

This is done using iscsit_start_kthreads() -> kthread_run() to start
new kthreads from within iscsi_post_login_handler(), and invoking
kthread_stop() from existing iscsit_close_connection() code.

Also, convert iscsit_logout_post_handler_closesession() code to use
cmpxchg when determing when iscsit_cause_connection_reinstatement()
needs to sleep waiting for completion.

Reported-by: Sagi Grimberg <sagig@mellanox.com>
Tested-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Slava Shwartsman <valyushash@gmail.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 47af861..163773f 100644 (file)
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -537,7 +537,7 @@ static struct iscsit_transport iscsi_target_transport = {
 
 static int __init iscsi_target_init_module(void)
 {
-       int ret = 0;
+       int ret = 0, size;
 
        pr_debug("iSCSI-Target "ISCSIT_VERSION"\n");
 
@@ -546,6 +546,7 @@ static int __init iscsi_target_init_module(void)
                pr_err("Unable to allocate memory for iscsit_global\n");
                return -1;
        }
+       spin_lock_init(&iscsit_global->ts_bitmap_lock);
        mutex_init(&auth_id_lock);
        spin_lock_init(&sess_idr_lock);
        idr_init(&tiqn_idr);
@@ -555,15 +556,11 @@ static int __init iscsi_target_init_module(void)
        if (ret < 0)
                goto out;
 
-       ret = iscsi_thread_set_init();
-       if (ret < 0)
+       size = BITS_TO_LONGS(ISCSIT_BITMAP_BITS) * sizeof(long);
+       iscsit_global->ts_bitmap = vzalloc(size);
+       if (!iscsit_global->ts_bitmap) {
+               pr_err("Unable to allocate iscsit_global->ts_bitmap\n");
                goto configfs_out;
-
-       if (iscsi_allocate_thread_sets(TARGET_THREAD_SET_COUNT) !=
-                       TARGET_THREAD_SET_COUNT) {
-               pr_err("iscsi_allocate_thread_sets() returned"
-                       " unexpected value!\n");
-               goto ts_out1;
        }
 
        lio_qr_cache = kmem_cache_create("lio_qr_cache",
@@ -572,7 +569,7 @@ static int __init iscsi_target_init_module(void)
        if (!lio_qr_cache) {
                pr_err("nable to kmem_cache_create() for"
                                " lio_qr_cache\n");
-               goto ts_out2;
+               goto bitmap_out;
        }
 
        lio_dr_cache = kmem_cache_create("lio_dr_cache",
@@ -617,10 +614,8 @@ dr_out:
        kmem_cache_destroy(lio_dr_cache);
 qr_out:
        kmem_cache_destroy(lio_qr_cache);
-ts_out2:
-       iscsi_deallocate_thread_sets();
-ts_out1:
-       iscsi_thread_set_free();
+bitmap_out:
+       vfree(iscsit_global->ts_bitmap);
 configfs_out:
        iscsi_target_deregister_configfs();
 out:
@@ -630,8 +625,6 @@ out:
 
 static void __exit iscsi_target_cleanup_module(void)
 {
-       iscsi_deallocate_thread_sets();
-       iscsi_thread_set_free();
        iscsit_release_discovery_tpg();
        iscsit_unregister_transport(&iscsi_target_transport);
        kmem_cache_destroy(lio_qr_cache);
@@ -641,6 +634,7 @@ static void __exit iscsi_target_cleanup_module(void)
 
        iscsi_target_deregister_configfs();
 
+       vfree(iscsit_global->ts_bitmap);
        kfree(iscsit_global);
 }
 
@@ -3709,17 +3703,16 @@ static int iscsit_send_reject(
 
 void iscsit_thread_get_cpumask(struct iscsi_conn *conn)
 {
-       struct iscsi_thread_set *ts = conn->thread_set;
        int ord, cpu;
        /*
-        * thread_id is assigned from iscsit_global->ts_bitmap from
-        * within iscsi_thread_set.c:iscsi_allocate_thread_sets()
+        * bitmap_id is assigned from iscsit_global->ts_bitmap from
+        * within iscsit_start_kthreads()
         *
-        * Here we use thread_id to determine which CPU that this
-        * iSCSI connection's iscsi_thread_set will be scheduled to
+        * Here we use bitmap_id to determine which CPU that this
+        * iSCSI connection's RX/TX threads will be scheduled to
         * execute upon.
         */
-       ord = ts->thread_id % cpumask_weight(cpu_online_mask);
+       ord = conn->bitmap_id % cpumask_weight(cpu_online_mask);
        for_each_online_cpu(cpu) {
                if (ord-- == 0) {
                        cpumask_set_cpu(cpu, conn->conn_cpumask);
@@ -3908,7 +3901,7 @@ check_rsp_state:
        switch (state) {
        case ISTATE_SEND_LOGOUTRSP:
                if (!iscsit_logout_post_handler(cmd, conn))
-                       goto restart;
+                       return -ECONNRESET;
                /* fall through */
        case ISTATE_SEND_STATUS:
        case ISTATE_SEND_ASYNCMSG:
@@ -3936,8 +3929,6 @@ check_rsp_state:
 
 err:
        return -1;
-restart:
-       return -EAGAIN;
 }
 
 static int iscsit_handle_response_queue(struct iscsi_conn *conn)
@@ -3964,21 +3955,13 @@ static int iscsit_handle_response_queue(struct iscsi_conn *conn)
 int iscsi_target_tx_thread(void *arg)
 {
        int ret = 0;
-       struct iscsi_conn *conn;
-       struct iscsi_thread_set *ts = arg;
+       struct iscsi_conn *conn = arg;
        /*
         * Allow ourselves to be interrupted by SIGINT so that a
         * connection recovery / failure event can be triggered externally.
         */
        allow_signal(SIGINT);
 
-restart:
-       conn = iscsi_tx_thread_pre_handler(ts);
-       if (!conn)
-               goto out;
-
-       ret = 0;
-
        while (!kthread_should_stop()) {
                /*
                 * Ensure that both TX and RX per connection kthreads
@@ -3987,11 +3970,9 @@ restart:
                iscsit_thread_check_cpumask(conn, current, 1);
 
                wait_event_interruptible(conn->queues_wq,
-                                        !iscsit_conn_all_queues_empty(conn) ||
-                                        ts->status == ISCSI_THREAD_SET_RESET);
+                                        !iscsit_conn_all_queues_empty(conn));
 
-               if ((ts->status == ISCSI_THREAD_SET_RESET) ||
-                    signal_pending(current))
+               if (signal_pending(current))
                        goto transport_err;
 
 get_immediate:
@@ -4002,15 +3983,14 @@ get_immediate:
                ret = iscsit_handle_response_queue(conn);
                if (ret == 1)
                        goto get_immediate;
-               else if (ret == -EAGAIN)
-                       goto restart;
+               else if (ret == -ECONNRESET)
+                       goto out;
                else if (ret < 0)
                        goto transport_err;
        }
 
 transport_err:
        iscsit_take_action_for_connection_exit(conn);
-       goto restart;
 out:
        return 0;
 }
@@ -4105,8 +4085,7 @@ int iscsi_target_rx_thread(void *arg)
        int ret;
        u8 buffer[ISCSI_HDR_LEN], opcode;
        u32 checksum = 0, digest = 0;
-       struct iscsi_conn *conn = NULL;
-       struct iscsi_thread_set *ts = arg;
+       struct iscsi_conn *conn = arg;
        struct kvec iov;
        /*
         * Allow ourselves to be interrupted by SIGINT so that a
@@ -4114,11 +4093,6 @@ int iscsi_target_rx_thread(void *arg)
         */
        allow_signal(SIGINT);
 
-restart:
-       conn = iscsi_rx_thread_pre_handler(ts);
-       if (!conn)
-               goto out;
-
        if (conn->conn_transport->transport_type == ISCSI_INFINIBAND) {
                struct completion comp;
                int rc;
@@ -4128,7 +4102,7 @@ restart:
                if (rc < 0)
                        goto transport_err;
 
-               goto out;
+               goto transport_err;
        }
 
        while (!kthread_should_stop()) {
@@ -4204,8 +4178,6 @@ transport_err:
        if (!signal_pending(current))
                atomic_set(&conn->transport_failed, 1);
        iscsit_take_action_for_connection_exit(conn);
-       goto restart;
-out:
        return 0;
 }
 
@@ -4261,7 +4233,24 @@ int iscsit_close_connection(
         */
        complete(&conn->conn_logout_comp);
 
-       iscsi_release_thread_set(conn);
+       if (!strcmp(current->comm, ISCSI_RX_THREAD_NAME)) {
+               if (conn->tx_thread &&
+                   cmpxchg(&conn->tx_thread_active, true, false)) {
+                       send_sig(SIGINT, conn->tx_thread, 1);
+                       kthread_stop(conn->tx_thread);
+               }
+       } else if (!strcmp(current->comm, ISCSI_TX_THREAD_NAME)) {
+               if (conn->rx_thread &&
+                   cmpxchg(&conn->rx_thread_active, true, false)) {
+                       send_sig(SIGINT, conn->rx_thread, 1);
+                       kthread_stop(conn->rx_thread);
+               }
+       }
+
+       spin_lock(&iscsit_global->ts_bitmap_lock);
+       bitmap_release_region(iscsit_global->ts_bitmap, conn->bitmap_id,
+                             get_order(1));
+       spin_unlock(&iscsit_global->ts_bitmap_lock);
 
        iscsit_stop_timers_for_cmds(conn);
        iscsit_stop_nopin_response_timer(conn);
@@ -4539,15 +4528,13 @@ static void iscsit_logout_post_handler_closesession(
        struct iscsi_conn *conn)
 {
        struct iscsi_session *sess = conn->sess;
-
-       iscsi_set_thread_clear(conn, ISCSI_CLEAR_TX_THREAD);
-       iscsi_set_thread_set_signal(conn, ISCSI_SIGNAL_TX_THREAD);
+       int sleep = cmpxchg(&conn->tx_thread_active, true, false);
 
        atomic_set(&conn->conn_logout_remove, 0);
        complete(&conn->conn_logout_comp);
 
        iscsit_dec_conn_usage_count(conn);
-       iscsit_stop_session(sess, 1, 1);
+       iscsit_stop_session(sess, sleep, sleep);
        iscsit_dec_session_usage_count(sess);
        target_put_session(sess->se_sess);
 }
@@ -4555,13 +4542,12 @@ static void iscsit_logout_post_handler_closesession(
 static void iscsit_logout_post_handler_samecid(
        struct iscsi_conn *conn)
 {
-       iscsi_set_thread_clear(conn, ISCSI_CLEAR_TX_THREAD);
-       iscsi_set_thread_set_signal(conn, ISCSI_SIGNAL_TX_THREAD);
+       int sleep = cmpxchg(&conn->tx_thread_active, true, false);
 
        atomic_set(&conn->conn_logout_remove, 0);
        complete(&conn->conn_logout_comp);
 
-       iscsit_cause_connection_reinstatement(conn, 1);
+       iscsit_cause_connection_reinstatement(conn, sleep);
        iscsit_dec_conn_usage_count(conn);
 }
 

diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c
index 1c197ba..d4e2159 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -861,7 +861,10 @@ void iscsit_connection_reinstatement_rcfr(struct iscsi_conn *conn)
        }
        spin_unlock_bh(&conn->state_lock);
 
-       iscsi_thread_set_force_reinstatement(conn);
+       if (conn->tx_thread && conn->tx_thread_active)
+               send_sig(SIGINT, conn->tx_thread, 1);
+       if (conn->rx_thread && conn->rx_thread_active)
+               send_sig(SIGINT, conn->rx_thread, 1);
 
 sleep:
        wait_for_completion(&conn->conn_wait_rcfr_comp);
@@ -886,10 +889,10 @@ void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep)
                return;
        }
 
-       if (iscsi_thread_set_force_reinstatement(conn) < 0) {
-               spin_unlock_bh(&conn->state_lock);
-               return;
-       }
+       if (conn->tx_thread && conn->tx_thread_active)
+               send_sig(SIGINT, conn->tx_thread, 1);
+       if (conn->rx_thread && conn->rx_thread_active)
+               send_sig(SIGINT, conn->rx_thread, 1);
 
        atomic_set(&conn->connection_reinstatement, 1);
        if (!sleep) {

diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 153fb66..345f073 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -699,6 +699,51 @@ static void iscsi_post_login_start_timers(struct iscsi_conn *conn)
                iscsit_start_nopin_timer(conn);
 }
 
+int iscsit_start_kthreads(struct iscsi_conn *conn)
+{
+       int ret = 0;
+
+       spin_lock(&iscsit_global->ts_bitmap_lock);
+       conn->bitmap_id = bitmap_find_free_region(iscsit_global->ts_bitmap,
+                                       ISCSIT_BITMAP_BITS, get_order(1));
+       spin_unlock(&iscsit_global->ts_bitmap_lock);
+
+       if (conn->bitmap_id < 0) {
+               pr_err("bitmap_find_free_region() failed for"
+                      " iscsit_start_kthreads()\n");
+               return -ENOMEM;
+       }
+
+       conn->tx_thread = kthread_run(iscsi_target_tx_thread, conn,
+                                     "%s", ISCSI_TX_THREAD_NAME);
+       if (IS_ERR(conn->tx_thread)) {
+               pr_err("Unable to start iscsi_target_tx_thread\n");
+               ret = PTR_ERR(conn->tx_thread);
+               goto out_bitmap;
+       }
+       conn->tx_thread_active = true;
+
+       conn->rx_thread = kthread_run(iscsi_target_rx_thread, conn,
+                                     "%s", ISCSI_RX_THREAD_NAME);
+       if (IS_ERR(conn->rx_thread)) {
+               pr_err("Unable to start iscsi_target_rx_thread\n");
+               ret = PTR_ERR(conn->rx_thread);
+               goto out_tx;
+       }
+       conn->rx_thread_active = true;
+
+       return 0;
+out_tx:
+       kthread_stop(conn->tx_thread);
+       conn->tx_thread_active = false;
+out_bitmap:
+       spin_lock(&iscsit_global->ts_bitmap_lock);
+       bitmap_release_region(iscsit_global->ts_bitmap, conn->bitmap_id,
+                             get_order(1));
+       spin_unlock(&iscsit_global->ts_bitmap_lock);
+       return ret;
+}
+
 int iscsi_post_login_handler(
        struct iscsi_np *np,
        struct iscsi_conn *conn,
@@ -709,7 +754,7 @@ int iscsi_post_login_handler(
        struct se_session *se_sess = sess->se_sess;
        struct iscsi_portal_group *tpg = sess->tpg;
        struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
-       struct iscsi_thread_set *ts;
+       int rc;
 
        iscsit_inc_conn_usage_count(conn);
 
@@ -724,7 +769,6 @@ int iscsi_post_login_handler(
        /*
         * SCSI Initiator -> SCSI Target Port Mapping
         */
-       ts = iscsi_get_thread_set();
        if (!zero_tsih) {
                iscsi_set_session_parameters(sess->sess_ops,
                                conn->param_list, 0);
@@ -751,9 +795,11 @@ int iscsi_post_login_handler(
                        sess->sess_ops->InitiatorName);
                spin_unlock_bh(&sess->conn_lock);
 
-               iscsi_post_login_start_timers(conn);
+               rc = iscsit_start_kthreads(conn);
+               if (rc)
+                       return rc;
 
-               iscsi_activate_thread_set(conn, ts);
+               iscsi_post_login_start_timers(conn);
                /*
                 * Determine CPU mask to ensure connection's RX and TX kthreads
                 * are scheduled on the same CPU.
@@ -810,8 +856,11 @@ int iscsi_post_login_handler(
                " iSCSI Target Portal Group: %hu\n", tpg->nsessions, tpg->tpgt);
        spin_unlock_bh(&se_tpg->session_lock);
 
+       rc = iscsit_start_kthreads(conn);
+       if (rc)
+               return rc;
+
        iscsi_post_login_start_timers(conn);
-       iscsi_activate_thread_set(conn, ts);
        /*
         * Determine CPU mask to ensure connection's RX and TX kthreads
         * are scheduled on the same CPU.

diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index d3583d3..dd0f3ab 100644 (file)
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -602,6 +602,11 @@ struct iscsi_conn {
        struct iscsi_session    *sess;
        /* Pointer to thread_set in use for this conn's threads */
        struct iscsi_thread_set *thread_set;
+       int                     bitmap_id;
+       int                     rx_thread_active;
+       struct task_struct      *rx_thread;
+       int                     tx_thread_active;
+       struct task_struct      *tx_thread;
        /* list_head for session connection list */
        struct list_head        conn_list;
 } ____cacheline_aligned;
@@ -871,10 +876,12 @@ struct iscsit_global {
        /* Unique identifier used for the authentication daemon */
        u32                     auth_id;
        u32                     inactive_ts;
+#define ISCSIT_BITMAP_BITS     262144
        /* Thread Set bitmap count */
        int                     ts_bitmap_count;
        /* Thread Set bitmap pointer */
        unsigned long           *ts_bitmap;
+       spinlock_t              ts_bitmap_lock;
        /* Used for iSCSI discovery session authentication */
        struct iscsi_node_acl   discovery_acl;
        struct iscsi_portal_group       *discovery_tpg;