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iscsi-target: Convert iscsi_thread_set usage to kthread.h
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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>
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Nicholas Bellinger committed Mar 26, 2015
1 parent 5bc6510 commit 88dcd2d
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Showing 4 changed files with 114 additions and 69 deletions.
104 changes: 45 additions & 59 deletions drivers/target/iscsi/iscsi_target.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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");

Expand All @@ -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);
Expand All @@ -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",
Expand All @@ -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",
Expand Down Expand Up @@ -617,10 +614,8 @@ static int __init iscsi_target_init_module(void)
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:
Expand All @@ -630,8 +625,6 @@ static int __init iscsi_target_init_module(void)

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);
Expand All @@ -641,6 +634,7 @@ static void __exit iscsi_target_cleanup_module(void)

iscsi_target_deregister_configfs();

vfree(iscsit_global->ts_bitmap);
kfree(iscsit_global);
}

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -3908,7 +3901,7 @@ iscsit_response_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int 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:
Expand Down Expand Up @@ -3936,8 +3929,6 @@ iscsit_response_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int state)

err:
return -1;
restart:
return -EAGAIN;
}

static int iscsit_handle_response_queue(struct iscsi_conn *conn)
Expand All @@ -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
Expand All @@ -3987,11 +3970,9 @@ int iscsi_target_tx_thread(void *arg)
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:
Expand All @@ -4002,15 +3983,14 @@ int iscsi_target_tx_thread(void *arg)
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;
}
Expand Down Expand Up @@ -4105,20 +4085,14 @@ 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
* connection recovery / failure event can be triggered externally.
*/
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;
Expand All @@ -4128,7 +4102,7 @@ int iscsi_target_rx_thread(void *arg)
if (rc < 0)
goto transport_err;

goto out;
goto transport_err;
}

while (!kthread_should_stop()) {
Expand Down Expand Up @@ -4204,8 +4178,6 @@ int iscsi_target_rx_thread(void *arg)
if (!signal_pending(current))
atomic_set(&conn->transport_failed, 1);
iscsit_take_action_for_connection_exit(conn);
goto restart;
out:
return 0;
}

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -4539,29 +4528,26 @@ 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);
}

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);
}

Expand Down
13 changes: 8 additions & 5 deletions drivers/target/iscsi/iscsi_target_erl0.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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) {
Expand Down
59 changes: 54 additions & 5 deletions drivers/target/iscsi/iscsi_target_login.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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);

Expand All @@ -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);
Expand All @@ -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.
Expand Down Expand Up @@ -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.
Expand Down
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