To remove the sess_cmd_lock this patch does:
- Removes the sess_cmd_list use from lio core, because it's been
moved to qla2xxx.
- Removes sess_tearing_down check in the IO path. Instead of using
that bit and the sess_cmd_lock, we rely on the cmd_count percpu
ref. To do this we switch to
percpu_ref_kill_and_confirm/percpu_ref_tryget_live.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 2 +-
drivers/infiniband/ulp/srpt/ib_srpt.c | 2 +-
drivers/scsi/qla2xxx/tcm_qla2xxx.c | 9 +---
drivers/target/target_core_tpg.c | 2 +-
drivers/target/target_core_transport.c | 77 ++++++++++++++-------------------
drivers/target/tcm_fc/tfc_sess.c | 2 +-
include/target/target_core_base.h | 6 +--
include/target/target_core_fabric.h | 2 +-
8 files changed, 43 insertions(+), 59 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 436e17f..3d21bf3 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2471,7 +2471,7 @@ static void isert_release_work(struct work_struct *work)
isert_info("iscsi_conn %p\n", conn);
if (conn->sess) {
- target_sess_cmd_list_set_waiting(conn->sess->se_sess);
+ target_stop_session(conn->sess->se_sess);
target_wait_for_sess_cmds(conn->sess->se_sess);
}
}
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 0065eb1..8377113 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -2084,7 +2084,7 @@ static void srpt_release_channel_work(struct work_struct *w)
se_sess = ch->sess;
BUG_ON(!se_sess);
- target_sess_cmd_list_set_waiting(se_sess);
+ target_stop_session(se_sess);
target_wait_for_sess_cmds(se_sess);
target_remove_session(se_sess);
diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
index e122da9..784b43f 100644
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -368,15 +368,10 @@ static void tcm_qla2xxx_put_sess(struct fc_port *sess)
static void tcm_qla2xxx_close_session(struct se_session *se_sess)
{
struct fc_port *sess = se_sess->fabric_sess_ptr;
- struct scsi_qla_host *vha;
- unsigned long flags;
BUG_ON(!sess);
- vha = sess->vha;
- spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
- target_sess_cmd_list_set_waiting(se_sess);
- spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
+ target_stop_session(se_sess);
sess->explicit_logout = 1;
tcm_qla2xxx_put_sess(sess);
@@ -831,7 +826,7 @@ static void tcm_qla2xxx_clear_nacl_from_fcport_map(struct fc_port *sess)
static void tcm_qla2xxx_shutdown_sess(struct fc_port *sess)
{
- target_sess_cmd_list_set_waiting(sess->se_sess);
+ target_stop_session(sess->se_sess);
}
static int tcm_qla2xxx_init_nodeacl(struct se_node_acl *se_nacl,
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index 62aa5fa..736847c 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -328,7 +328,7 @@ static void target_shutdown_sessions(struct se_node_acl *acl)
restart:
spin_lock_irqsave(&acl->nacl_sess_lock, flags);
list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
- if (sess->sess_tearing_down)
+ if (atomic_read(&sess->stopped))
continue;
list_del_init(&sess->sess_acl_list);
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 465b6583..b228c66 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -215,7 +215,7 @@ static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
{
struct se_session *sess = container_of(ref, typeof(*sess), cmd_count);
- wake_up(&sess->cmd_list_wq);
+ wake_up(&sess->cmd_count_wq);
}
/**
@@ -228,9 +228,10 @@ int transport_init_session(struct se_session *se_sess)
{
INIT_LIST_HEAD(&se_sess->sess_list);
INIT_LIST_HEAD(&se_sess->sess_acl_list);
- INIT_LIST_HEAD(&se_sess->sess_cmd_list);
spin_lock_init(&se_sess->sess_cmd_lock);
- init_waitqueue_head(&se_sess->cmd_list_wq);
+ init_waitqueue_head(&se_sess->cmd_count_wq);
+ init_completion(&se_sess->stop_done);
+ atomic_set(&se_sess->stopped, 0);
return percpu_ref_init(&se_sess->cmd_count,
target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
}
@@ -239,11 +240,11 @@ int transport_init_session(struct se_session *se_sess)
void transport_uninit_session(struct se_session *se_sess)
{
/*
- * Drivers like iscsi and loop do not call
- * target_sess_cmd_list_set_waiting during session shutdown so we
- * have to drop the ref taken at init time here.
+ * Drivers like iscsi and loop do not call target_stop_session
+ * during session shutdown so we have to drop the ref taken at init
+ * time here.
*/
- if (!se_sess->sess_tearing_down)
+ if (!atomic_read(&se_sess->stopped))
percpu_ref_put(&se_sess->cmd_count);
percpu_ref_exit(&se_sess->cmd_count);
@@ -1632,9 +1633,8 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess
if (flags & TARGET_SCF_UNKNOWN_SIZE)
se_cmd->unknown_data_length = 1;
/*
- * Obtain struct se_cmd->cmd_kref reference and add new cmd to
- * se_sess->sess_cmd_list. A second kref_get here is necessary
- * for fabrics using TARGET_SCF_ACK_KREF that expect a second
+ * Obtain struct se_cmd->cmd_kref reference. A second kref_get here is
+ * necessary for fabrics using TARGET_SCF_ACK_KREF that expect a second
* kref_put() to happen during fabric packet acknowledgement.
*/
ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
@@ -2763,14 +2763,13 @@ int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
EXPORT_SYMBOL(transport_generic_free_cmd);
/**
- * target_get_sess_cmd - Add command to active ->sess_cmd_list
+ * target_get_sess_cmd - Verify the session is accepting cmds and take ref
* @se_cmd: command descriptor to add
* @ack_kref: Signal that fabric will perform an ack target_put_sess_cmd()
*/
int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
{
struct se_session *se_sess = se_cmd->se_sess;
- unsigned long flags;
int ret = 0;
/*
@@ -2785,15 +2784,8 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
se_cmd->se_cmd_flags |= SCF_ACK_KREF;
}
- spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
- if (se_sess->sess_tearing_down) {
+ if (!percpu_ref_tryget_live(&se_sess->cmd_count))
ret = -ESHUTDOWN;
- goto out;
- }
- list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
- percpu_ref_get(&se_sess->cmd_count);
-out:
- spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
if (ret && ack_kref)
target_put_sess_cmd(se_cmd);
@@ -2818,13 +2810,6 @@ static void target_release_cmd_kref(struct kref *kref)
struct se_session *se_sess = se_cmd->se_sess;
struct completion *free_compl = se_cmd->free_compl;
struct completion *abrt_compl = se_cmd->abrt_compl;
- unsigned long flags;
-
- if (se_sess) {
- spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
- list_del_init(&se_cmd->se_cmd_list);
- spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
- }
target_free_cmd_mem(se_cmd);
se_cmd->se_tfo->release_cmd(se_cmd);
@@ -2952,21 +2937,25 @@ void target_show_cmd(const char *pfx, struct se_cmd *cmd)
}
EXPORT_SYMBOL(target_show_cmd);
+static void target_stop_session_confirm(struct percpu_ref *ref)
+{
+ struct se_session *se_sess = container_of(ref, struct se_session,
+ cmd_count);
+ complete_all(&se_sess->stop_done);
+}
+
/**
- * target_sess_cmd_list_set_waiting - Set sess_tearing_down so no new commands are queued.
- * @se_sess: session to flag
+ * target_stop_session - Stop new IO from being queued on the session.
+ * @se_sess: session to stop
*/
-void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
+void target_stop_session(struct se_session *se_sess)
{
- unsigned long flags;
-
- spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
- se_sess->sess_tearing_down = 1;
- spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
-
- percpu_ref_kill(&se_sess->cmd_count);
+ pr_debug("Stopping session queue.\n");
+ if (atomic_cmpxchg(&se_sess->stopped, 0, 1) == 0)
+ percpu_ref_kill_and_confirm(&se_sess->cmd_count,
+ target_stop_session_confirm);
}
-EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
+EXPORT_SYMBOL(target_stop_session);
/**
* target_wait_for_sess_cmds - Wait for outstanding commands
@@ -2974,19 +2963,19 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
*/
void target_wait_for_sess_cmds(struct se_session *se_sess)
{
- struct se_cmd *cmd;
int ret;
- WARN_ON_ONCE(!se_sess->sess_tearing_down);
+ WARN_ON_ONCE(!atomic_read(&se_sess->stopped));
do {
- ret = wait_event_timeout(se_sess->cmd_list_wq,
+ pr_debug("Waiting for running cmds to complete.\n");
+ ret = wait_event_timeout(se_sess->cmd_count_wq,
percpu_ref_is_zero(&se_sess->cmd_count),
180 * HZ);
- list_for_each_entry(cmd, &se_sess->sess_cmd_list, se_cmd_list)
- target_show_cmd("session shutdown: still waiting for ",
- cmd);
} while (ret <= 0);
+
+ wait_for_completion(&se_sess->stop_done);
+ pr_debug("Waiting for cmds done.\n");
}
EXPORT_SYMBOL(target_wait_for_sess_cmds);
diff --git a/drivers/target/tcm_fc/tfc_sess.c b/drivers/target/tcm_fc/tfc_sess.c
index 4fd6a1d..23ce506 100644
--- a/drivers/target/tcm_fc/tfc_sess.c
+++ b/drivers/target/tcm_fc/tfc_sess.c
@@ -275,7 +275,7 @@ static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
static void ft_close_sess(struct ft_sess *sess)
{
- target_sess_cmd_list_set_waiting(sess->se_sess);
+ target_stop_session(sess->se_sess);
target_wait_for_sess_cmds(sess->se_sess);
ft_sess_put(sess);
}
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index b3c9946..2824463 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -608,7 +608,7 @@ static inline struct se_node_acl *fabric_stat_to_nacl(struct config_item *item)
}
struct se_session {
- unsigned sess_tearing_down:1;
+ atomic_t stopped;
u64 sess_bin_isid;
enum target_prot_op sup_prot_ops;
enum target_prot_type sess_prot_type;
@@ -618,9 +618,9 @@ struct se_session {
struct percpu_ref cmd_count;
struct list_head sess_list;
struct list_head sess_acl_list;
- struct list_head sess_cmd_list;
spinlock_t sess_cmd_lock;
- wait_queue_head_t cmd_list_wq;
+ wait_queue_head_t cmd_count_wq;
+ struct completion stop_done;
void *sess_cmd_map;
struct sbitmap_queue sess_tag_pool;
};
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 6adf4d7..d60a3eb 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -178,7 +178,7 @@ int transport_send_check_condition_and_sense(struct se_cmd *,
int target_send_busy(struct se_cmd *cmd);
int target_get_sess_cmd(struct se_cmd *, bool);
int target_put_sess_cmd(struct se_cmd *);
-void target_sess_cmd_list_set_waiting(struct se_session *);
+void target_stop_session(struct se_session *se_sess);
void target_wait_for_sess_cmds(struct se_session *);
void target_show_cmd(const char *pfx, struct se_cmd *cmd);
--
1.8.3.1
