[PATCH-3.14.y 0/3] target: stable backports

[PATCH-3.14.y 0/3] target: stable backports

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@linux-iscsi.org>

Hi Greg-KH & Sagi,

Here are three outstanding backport patches that have been updated
to apply against v3.14.47.

Please apply to queue-3.14.

Also, there are still two remaining iser-target patches marked for
3.14.y+, that currently don't apply due to additional patch dependencies:

    364189f0a iser-target: Fix session hang in case of an rdma read DIF error
    524630d58 iser-target: Fix possible use-after-free
    
Sagi, please consider including the extra dependencies if possible,
or consider updating these patches to apply against 3.14 code.

Thank you,

--nab

Nicholas Bellinger (1):
  iscsi-target: Convert iscsi_thread_set usage to kthread.h

Sagi Grimberg (2):
  iser-target: Fix possible deadlock in RDMA_CM connection error
  iser-target: release stale iser connections

 drivers/infiniband/ulp/isert/ib_isert.c   |  32 +++++++--
 drivers/target/iscsi/iscsi_target.c       | 104 +++++++++++++-----------------
 drivers/target/iscsi/iscsi_target_core.h  |   7 ++
 drivers/target/iscsi/iscsi_target_erl0.c  |  13 ++--
 drivers/target/iscsi/iscsi_target_login.c |  59 +++++++++++++++--
 5 files changed, 140 insertions(+), 75 deletions(-)

-- 
1.8.5.3

[PATCH-3.14.y 1/3] iscsi-target: Convert iscsi_thread_set usage to kthread.h

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@linux-iscsi.org>

commit 88dcd2dab5c23b1c9cfc396246d8f476c872f0ca upstream.

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>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/iscsi/iscsi_target.c       | 104 +++++++++++++-----------------
 drivers/target/iscsi/iscsi_target_core.h  |   7 ++
 drivers/target/iscsi/iscsi_target_erl0.c  |  13 ++--
 drivers/target/iscsi/iscsi_target_login.c |  59 +++++++++++++++--
 4 files changed, 114 insertions(+), 69 deletions(-)

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index b61c555..c8d7b30 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -518,7 +518,7 @@ 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");
 
@@ -527,6 +527,7 @@ 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);
@@ -536,15 +537,11 @@ 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",
@@ -553,7 +550,7 @@ 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",
@@ -597,10 +594,8 @@ 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:
@@ -610,8 +605,6 @@ 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);
@@ -621,6 +614,7 @@ static void __exit iscsi_target_cleanup_module(void)
 
 	iscsi_target_deregister_configfs();
 
+	vfree(iscsit_global->ts_bitmap);
 	kfree(iscsit_global);
 }
 
@@ -3653,17 +3647,16 @@ 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);
@@ -3855,7 +3848,7 @@ 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:
@@ -3883,8 +3876,6 @@ check_rsp_state:
 
 err:
 	return -1;
-restart:
-	return -EAGAIN;
 }
 
 static int iscsit_handle_response_queue(struct iscsi_conn *conn)
@@ -3911,21 +3902,13 @@ 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
@@ -3934,11 +3917,9 @@ 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:
@@ -3949,15 +3930,14 @@ 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;
 }
@@ -4046,8 +4026,7 @@ 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
@@ -4055,11 +4034,6 @@ 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;
@@ -4069,7 +4043,7 @@ restart:
 		if (rc < 0)
 			goto transport_err;
 
-		goto out;
+		goto transport_err;
 	}
 
 	while (!kthread_should_stop()) {
@@ -4145,8 +4119,6 @@ transport_err:
 	if (!signal_pending(current))
 		atomic_set(&conn->transport_failed, 1);
 	iscsit_take_action_for_connection_exit(conn);
-	goto restart;
-out:
 	return 0;
 }
 
@@ -4208,7 +4180,24 @@ int iscsit_close_connection(
 	if (conn->conn_transport->transport_type == ISCSI_TCP)
 		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);
@@ -4487,15 +4476,13 @@ 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);
 }
@@ -4503,13 +4490,12 @@ 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_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 1d4a8c8..825b579 100644
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -601,6 +601,11 @@ 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;
@@ -869,10 +874,12 @@ 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;
diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c
index 0d1e6ee..7396d90 100644
--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -864,7 +864,10 @@ 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);
@@ -889,10 +892,10 @@ 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 c5d3811..449df09 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -681,6 +681,51 @@ 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,
@@ -691,7 +736,7 @@ 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);
 
@@ -706,7 +751,6 @@ 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);
@@ -733,9 +777,11 @@ 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.
@@ -792,8 +838,11 @@ 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.
-- 
1.8.5.3

[PATCH-3.14.y 2/3] iser-target: Fix possible deadlock in RDMA_CM connection error

[Nicholas A. Bellinger]

From: Sagi Grimberg <sagig@mellanox.com>

commit 4a579da2586bd3b79b025947ea24ede2bbfede62 upstream.

Before we reach to connection established we may get an
error event. In this case the core won't teardown this
connection (never established it), so we take care of freeing
it ourselves.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 6014227..d6f05b2 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -206,7 +206,7 @@ fail:
 static void
 isert_free_rx_descriptors(struct isert_conn *isert_conn)
 {
-	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct ib_device *ib_dev = isert_conn->conn_device->ib_device;
 	struct iser_rx_desc *rx_desc;
 	int i;
 
@@ -647,9 +647,9 @@ out:
 static void
 isert_connect_release(struct isert_conn *isert_conn)
 {
-	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
 	struct isert_device *device = isert_conn->conn_device;
 	int cq_index;
+	struct ib_device *ib_dev = device->ib_device;
 
 	pr_debug("Entering isert_connect_release(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -657,7 +657,8 @@ isert_connect_release(struct isert_conn *isert_conn)
 		isert_conn_free_fastreg_pool(isert_conn);
 
 	isert_free_rx_descriptors(isert_conn);
-	rdma_destroy_id(isert_conn->conn_cm_id);
+	if (isert_conn->conn_cm_id)
+		rdma_destroy_id(isert_conn->conn_cm_id);
 
 	if (isert_conn->conn_qp) {
 		cq_index = ((struct isert_cq_desc *)
@@ -815,12 +816,15 @@ isert_disconnected_handler(struct rdma_cm_id *cma_id,
 	return 0;
 }
 
-static void
+static int
 isert_connect_error(struct rdma_cm_id *cma_id)
 {
 	struct isert_conn *isert_conn = cma_id->qp->qp_context;
 
+	isert_conn->conn_cm_id = NULL;
 	isert_put_conn(isert_conn);
+
+	return -1;
 }
 
 static int
@@ -850,7 +854,7 @@ isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	case RDMA_CM_EVENT_REJECTED:       /* FALLTHRU */
 	case RDMA_CM_EVENT_UNREACHABLE:    /* FALLTHRU */
 	case RDMA_CM_EVENT_CONNECT_ERROR:
-		isert_connect_error(cma_id);
+		ret = isert_connect_error(cma_id);
 		break;
 	default:
 		pr_err("Unhandled RDMA CMA event: %d\n", event->event);
-- 
1.8.5.3

[PATCH-3.14.y 3/3] iser-target: release stale iser connections

[Nicholas A. Bellinger]

From: Sagi Grimberg <sagig@mellanox.com>

commit 2f1b6b7d9a815f341b18dfd26a363f37d4d3c96a upstream.

When receiving a new iser connect request we serialize
the pending requests by adding the newly created iser connection
to the np accept list and let the login thread process the connect
request one by one (np_accept_wait).

In case we received a disconnect request before the iser_conn
has begun processing (still linked in np_accept_list) we should
detach it from the list and clean it up and not have the login
thread process a stale connection. We do it only when the connection
state is not already terminating (initiator driven disconnect) as
this might lead us to access np_accept_mutex after the np was released
in live shutdown scenarios.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jenny Falkovich <jennyf@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index d6f05b2..dd2b610 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -59,6 +59,8 @@ static int
 isert_rdma_accept(struct isert_conn *isert_conn);
 struct rdma_cm_id *isert_setup_id(struct isert_np *isert_np);
 
+static void isert_release_work(struct work_struct *work);
+
 static void
 isert_qp_event_callback(struct ib_event *e, void *context)
 {
@@ -534,6 +536,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	mutex_init(&isert_conn->conn_mutex);
 	spin_lock_init(&isert_conn->conn_lock);
 	INIT_LIST_HEAD(&isert_conn->conn_fr_pool);
+	INIT_WORK(&isert_conn->release_work, isert_release_work);
 
 	isert_conn->conn_cm_id = cma_id;
 	isert_conn->responder_resources = event->param.conn.responder_resources;
@@ -800,6 +803,7 @@ isert_disconnected_handler(struct rdma_cm_id *cma_id,
 {
 	struct isert_np *isert_np = cma_id->context;
 	struct isert_conn *isert_conn;
+	bool terminating = false;
 
 	if (isert_np->np_cm_id == cma_id)
 		return isert_np_cma_handler(cma_id->context, event);
@@ -807,12 +811,25 @@ isert_disconnected_handler(struct rdma_cm_id *cma_id,
 	isert_conn = cma_id->qp->qp_context;
 
 	mutex_lock(&isert_conn->conn_mutex);
+	terminating = (isert_conn->state == ISER_CONN_TERMINATING);
 	isert_conn_terminate(isert_conn);
 	mutex_unlock(&isert_conn->conn_mutex);
 
 	pr_info("conn %p completing conn_wait\n", isert_conn);
 	complete(&isert_conn->conn_wait);
 
+	if (terminating)
+		goto out;
+
+	mutex_lock(&isert_np->np_accept_mutex);
+	if (!list_empty(&isert_conn->conn_accept_node)) {
+		list_del_init(&isert_conn->conn_accept_node);
+		isert_put_conn(isert_conn);
+		queue_work(isert_release_wq, &isert_conn->release_work);
+	}
+	mutex_unlock(&isert_np->np_accept_mutex);
+
+out:
 	return 0;
 }
 
@@ -2948,7 +2965,6 @@ static void isert_wait_conn(struct iscsi_conn *conn)
 
 	wait_for_completion(&isert_conn->conn_wait_comp_err);
 
-	INIT_WORK(&isert_conn->release_work, isert_release_work);
 	queue_work(isert_release_wq, &isert_conn->release_work);
 }
 
-- 
1.8.5.3

Re: [PATCH-3.14.y 0/3] target: stable backports

[Nicholas A. Bellinger]

Hi Greg,

Would you be so kind to queue this series up for v3.14.y code..?

There are a couple more fixes in flight for v4.2-rc that depend upon
these patches.

Thank you,

--nab

On Tue, 2015-07-07 at 05:40 +0000, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
> 
> Hi Greg-KH & Sagi,
> 
> Here are three outstanding backport patches that have been updated
> to apply against v3.14.47.
> 
> Please apply to queue-3.14.
> 
> Also, there are still two remaining iser-target patches marked for
> 3.14.y+, that currently don't apply due to additional patch dependencies:
> 
>     364189f0a iser-target: Fix session hang in case of an rdma read DIF error
>     524630d58 iser-target: Fix possible use-after-free
>     
> Sagi, please consider including the extra dependencies if possible,
> or consider updating these patches to apply against 3.14 code.
> 
> Thank you,
> 
> --nab
> 
> Nicholas Bellinger (1):
>   iscsi-target: Convert iscsi_thread_set usage to kthread.h
> 
> Sagi Grimberg (2):
>   iser-target: Fix possible deadlock in RDMA_CM connection error
>   iser-target: release stale iser connections
> 
>  drivers/infiniband/ulp/isert/ib_isert.c   |  32 +++++++--
>  drivers/target/iscsi/iscsi_target.c       | 104 +++++++++++++-----------------
>  drivers/target/iscsi/iscsi_target_core.h  |   7 ++
>  drivers/target/iscsi/iscsi_target_erl0.c  |  13 ++--
>  drivers/target/iscsi/iscsi_target_login.c |  59 +++++++++++++++--
>  5 files changed, 140 insertions(+), 75 deletions(-)
>