Commit fdbd1c5e authored by Christof Schmitt's avatar Christof Schmitt Committed by James Bottomley
Browse files

[SCSI] zfcp: Allow running unit/LUN shutdown without acquiring reference 



With the change for the LUN data to be part of the scsi_device, the
slave_destroy callback will be the final call to the
zfcp_erp_unit_shutdown function. The erp tries to acquire a reference
to run the action asynchronously and fail, if it cannot get the
reference. But calling scsi_device_get from slave_destroy will fail,
because the scsi_device is already in the state SDEV_DEL.

Introduce a new call into the zfcp erp to solve this: The function
zfcp_erp_unit_shutdown_wait will close the LUN and wait for the erp to
finish without acquiring an additional reference. The wait allows to
omit the reference; the caller waiting for the erp to finish already
has a reference that holds the struct in place.

Reviewed-by: default avatarSwen Schillig <swen@vnet.ibm.com>
Signed-off-by: default avatarChristof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent e4b9857f

drivers/s390/scsi/zfcp_erp.c

+62 −36
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ enum zfcp_erp_act_flags { 
	ZFCP_STATUS_ERP_DISMISSING	= 0x00100000,

	ZFCP_STATUS_ERP_DISMISSED	= 0x00200000,

	ZFCP_STATUS_ERP_LOWMEM		= 0x00400000,

	ZFCP_STATUS_ERP_NO_REF		= 0x00800000,

};



enum zfcp_erp_steps {
@@ -169,22 +170,22 @@ static int zfcp_erp_required_act(int want, struct zfcp_adapter *adapter, 
	return need;

}



static struct zfcp_erp_action *zfcp_erp_setup_act(int need,

static struct zfcp_erp_action *zfcp_erp_setup_act(int need, u32 act_status,

						  struct zfcp_adapter *adapter,

						  struct zfcp_port *port,

						  struct zfcp_unit *unit)

{

	struct zfcp_erp_action *erp_action;

	u32 status = 0;



	switch (need) {

	case ZFCP_ERP_ACTION_REOPEN_UNIT:

		if (!(act_status & ZFCP_STATUS_ERP_NO_REF))

			if (!get_device(&unit->dev))

				return NULL;

		atomic_set_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &unit->status);

		erp_action = &unit->erp_action;

		if (!(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_RUNNING))

			status = ZFCP_STATUS_ERP_CLOSE_ONLY;

			act_status |= ZFCP_STATUS_ERP_CLOSE_ONLY;

		break;



	case ZFCP_ERP_ACTION_REOPEN_PORT:
@@ -195,7 +196,7 @@ static struct zfcp_erp_action *zfcp_erp_setup_act(int need, 
		atomic_set_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &port->status);

		erp_action = &port->erp_action;

		if (!(atomic_read(&port->status) & ZFCP_STATUS_COMMON_RUNNING))

			status = ZFCP_STATUS_ERP_CLOSE_ONLY;

			act_status |= ZFCP_STATUS_ERP_CLOSE_ONLY;

		break;



	case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
@@ -205,7 +206,7 @@ static struct zfcp_erp_action *zfcp_erp_setup_act(int need, 
		erp_action = &adapter->erp_action;

		if (!(atomic_read(&adapter->status) &

		      ZFCP_STATUS_COMMON_RUNNING))

			status = ZFCP_STATUS_ERP_CLOSE_ONLY;

			act_status |= ZFCP_STATUS_ERP_CLOSE_ONLY;

		break;



	default:
@@ -217,14 +218,15 @@ static struct zfcp_erp_action *zfcp_erp_setup_act(int need, 
	erp_action->port = port;

	erp_action->unit = unit;

	erp_action->action = need;

	erp_action->status = status;

	erp_action->status = act_status;



	return erp_action;

}



static int zfcp_erp_action_enqueue(int want, struct zfcp_adapter *adapter,

				   struct zfcp_port *port,

				   struct zfcp_unit *unit, char *id, void *ref)

				   struct zfcp_unit *unit, char *id, void *ref,

				   u32 act_status)

{

	int retval = 1, need;

	struct zfcp_erp_action *act = NULL;
@@ -236,10 +238,10 @@ static int zfcp_erp_action_enqueue(int want, struct zfcp_adapter *adapter, 
	if (!need)

		goto out;



	atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING, &adapter->status);

	act = zfcp_erp_setup_act(need, adapter, port, unit);

	act = zfcp_erp_setup_act(need, act_status, adapter, port, unit);

	if (!act)

		goto out;

	atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING, &adapter->status);

	++adapter->erp_total_count;

	list_add_tail(&act->list, &adapter->erp_ready_head);

	wake_up(&adapter->erp_ready_wq);
@@ -262,7 +264,7 @@ static int _zfcp_erp_adapter_reopen(struct zfcp_adapter *adapter, 
		return -EIO;

	}

	return zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_ADAPTER,

				       adapter, NULL, NULL, id, ref);

				       adapter, NULL, NULL, id, ref, 0);

}



/**
@@ -285,7 +287,7 @@ void zfcp_erp_adapter_reopen(struct zfcp_adapter *adapter, int clear, 
		zfcp_erp_adapter_failed(adapter, "erareo1", NULL);

	else

		zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_ADAPTER, adapter,

					NULL, NULL, id, ref);

					NULL, NULL, id, ref, 0);

	write_unlock_irqrestore(&adapter->erp_lock, flags);

}
@@ -317,20 +319,6 @@ void zfcp_erp_port_shutdown(struct zfcp_port *port, int clear, char *id, 
	zfcp_erp_port_reopen(port, clear | flags, id, ref);

}



/**

 * zfcp_erp_unit_shutdown - Shutdown unit

 * @unit: Unit to shut down.

 * @clear: Status flags to clear.

 * @id: Id for debug trace event.

 * @ref: Reference for debug trace event.

 */

void zfcp_erp_unit_shutdown(struct zfcp_unit *unit, int clear, char *id,

			    void *ref)

{

	int flags = ZFCP_STATUS_COMMON_RUNNING | ZFCP_STATUS_COMMON_ERP_FAILED;

	zfcp_erp_unit_reopen(unit, clear | flags, id, ref);

}



static void zfcp_erp_port_block(struct zfcp_port *port, int clear)

{

	zfcp_erp_modify_port_status(port, "erpblk1", NULL,
@@ -348,7 +336,7 @@ static void _zfcp_erp_port_forced_reopen(struct zfcp_port *port, 
		return;



	zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_PORT_FORCED,

				port->adapter, port, NULL, id, ref);

				port->adapter, port, NULL, id, ref, 0);

}



/**
@@ -381,7 +369,7 @@ static int _zfcp_erp_port_reopen(struct zfcp_port *port, int clear, char *id, 
	}



	return zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_PORT,

				       port->adapter, port, NULL, id, ref);

				       port->adapter, port, NULL, id, ref, 0);

}



/**
@@ -412,7 +400,7 @@ static void zfcp_erp_unit_block(struct zfcp_unit *unit, int clear_mask) 
}



static void _zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear, char *id,

				  void *ref)

				  void *ref, u32 act_status)

{

	struct zfcp_adapter *adapter = unit->port->adapter;
@@ -422,7 +410,7 @@ static void _zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear, char *id, 
		return;



	zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_UNIT,

				adapter, unit->port, unit, id, ref);

				adapter, unit->port, unit, id, ref, act_status);

}



/**
@@ -439,8 +427,45 @@ void zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear, char *id, 
	struct zfcp_adapter *adapter = port->adapter;



	write_lock_irqsave(&adapter->erp_lock, flags);

	_zfcp_erp_unit_reopen(unit, clear, id, ref);

	_zfcp_erp_unit_reopen(unit, clear, id, ref, 0);

	write_unlock_irqrestore(&adapter->erp_lock, flags);

}



/**

 * zfcp_erp_unit_shutdown - Shutdown unit

 * @unit: Unit to shut down.

 * @clear: Status flags to clear.

 * @id: Id for debug trace event.

 * @ref: Reference for debug trace event.

 */

void zfcp_erp_unit_shutdown(struct zfcp_unit *unit, int clear, char *id,

			    void *ref)

{

	int flags = ZFCP_STATUS_COMMON_RUNNING | ZFCP_STATUS_COMMON_ERP_FAILED;

	zfcp_erp_unit_reopen(unit, clear | flags, id, ref);

}



/**

 * zfcp_erp_unit_shutdown_wait - Shutdown unit and wait for erp completion

 * @unit: Unit to shut down.

 * @id: Id for debug trace event.

 *

 * Do not acquire a reference for the unit when creating the ERP

 * action. It is safe, because this function waits for the ERP to

 * complete first.

 */

void zfcp_erp_unit_shutdown_wait(struct zfcp_unit *unit, char *id)

{

	unsigned long flags;

	struct zfcp_port *port = unit->port;

	struct zfcp_adapter *adapter = port->adapter;

	int clear = ZFCP_STATUS_COMMON_RUNNING | ZFCP_STATUS_COMMON_ERP_FAILED;



	write_lock_irqsave(&adapter->erp_lock, flags);

	_zfcp_erp_unit_reopen(unit, clear, id, NULL, ZFCP_STATUS_ERP_NO_REF);

	write_unlock_irqrestore(&adapter->erp_lock, flags);



	zfcp_erp_wait(adapter);

}



static int status_change_set(unsigned long mask, atomic_t *status)
@@ -566,7 +591,7 @@ static void _zfcp_erp_unit_reopen_all(struct zfcp_port *port, int clear, 


	read_lock(&port->unit_list_lock);

	list_for_each_entry(unit, &port->unit_list, list)

		_zfcp_erp_unit_reopen(unit, clear, id, ref);

		_zfcp_erp_unit_reopen(unit, clear, id, ref, 0);

	read_unlock(&port->unit_list_lock);

}
@@ -583,7 +608,7 @@ static void zfcp_erp_strategy_followup_failed(struct zfcp_erp_action *act) 
		_zfcp_erp_port_reopen(act->port, 0, "ersff_3", NULL);

		break;

	case ZFCP_ERP_ACTION_REOPEN_UNIT:

		_zfcp_erp_unit_reopen(act->unit, 0, "ersff_4", NULL);

		_zfcp_erp_unit_reopen(act->unit, 0, "ersff_4", NULL, 0);

		break;

	}

}
@@ -1143,7 +1168,7 @@ static int zfcp_erp_strategy_statechange(struct zfcp_erp_action *act, int ret) 
		if (zfcp_erp_strat_change_det(&unit->status, erp_status)) {

			_zfcp_erp_unit_reopen(unit,

					      ZFCP_STATUS_COMMON_ERP_FAILED,

					      "ersscg3", NULL);

					      "ersscg3", NULL, 0);

			return ZFCP_ERP_EXIT;

		}

		break;
@@ -1191,6 +1216,7 @@ static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result) 


	switch (act->action) {

	case ZFCP_ERP_ACTION_REOPEN_UNIT:

		if (!(act->status & ZFCP_STATUS_ERP_NO_REF))

			put_device(&unit->dev);

		break;

drivers/s390/scsi/zfcp_ext.h

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ extern void zfcp_erp_modify_unit_status(struct zfcp_unit *, char *, void *, u32, 
					int);

extern void zfcp_erp_unit_reopen(struct zfcp_unit *, int, char *, void *);

extern void zfcp_erp_unit_shutdown(struct zfcp_unit *, int, char *, void *);

extern void zfcp_erp_unit_shutdown_wait(struct zfcp_unit *, char *);

extern void zfcp_erp_unit_failed(struct zfcp_unit *, char *, void *);

extern int  zfcp_erp_thread_setup(struct zfcp_adapter *);

extern void zfcp_erp_thread_kill(struct zfcp_adapter *);

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