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
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -537,7 +537,7 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
iscsi_target_deregister_configfs();
+ vfree(iscsit_global->ts_bitmap);
kfree(iscsit_global);
}
@@ -3709,17 +3703,16 @@
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 @@
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 @@
err:
return -1;
-restart:
- return -EAGAIN;
}
static int iscsit_handle_response_queue(struct iscsi_conn *conn)
@@ -3964,21 +3955,13 @@
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 @@
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 @@
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 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 @@
*/
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 @@
if (rc < 0)
goto transport_err;
- goto out;
+ goto transport_err;
}
while (!kthread_should_stop()) {
@@ -4204,8 +4178,6 @@
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 @@
*/
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 @@
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_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);
}