From: Christof Schmitt <christof.schmitt@xxxxxxxxxx>
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: Swen Schillig <swen@xxxxxxxxxxxx>
Signed-off-by: Christof Schmitt <christof.schmitt@xxxxxxxxxx>
---
drivers/s390/scsi/zfcp_erp.c | 98 +++++++++++++++++++++++++++----------------
drivers/s390/scsi/zfcp_ext.h | 1
2 files changed, 63 insertions(+), 36 deletions(-)
diff -urpN linux-2.6/drivers/s390/scsi/zfcp_erp.c linux-2.6-patched/drivers/s390/scsi/zfcp_erp.c
--- linux-2.6/drivers/s390/scsi/zfcp_erp.c 2010-09-08 08:49:06.000000000 +0200
+++ linux-2.6-patched/drivers/s390/scsi/zfcp_erp.c 2010-09-08 08:49:28.000000000 +0200
@@ -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 wan
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 (!get_device(&unit->dev))
- return NULL;
+ 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_
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_
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_
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 w
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(stru
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
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_
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
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
}
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 z
}
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
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_un
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(st
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_f
_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
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;
@@ -1191,7 +1216,8 @@ static void zfcp_erp_action_cleanup(stru
switch (act->action) {
case ZFCP_ERP_ACTION_REOPEN_UNIT:
- put_device(&unit->dev);
+ if (!(act->status & ZFCP_STATUS_ERP_NO_REF))
+ put_device(&unit->dev);
break;
case ZFCP_ERP_ACTION_REOPEN_PORT:
diff -urpN linux-2.6/drivers/s390/scsi/zfcp_ext.h linux-2.6-patched/drivers/s390/scsi/zfcp_ext.h
--- linux-2.6/drivers/s390/scsi/zfcp_ext.h 2010-09-08 08:49:27.000000000 +0200
+++ linux-2.6-patched/drivers/s390/scsi/zfcp_ext.h 2010-09-08 08:49:28.000000000 +0200
@@ -80,6 +80,7 @@ extern void zfcp_erp_modify_unit_status(
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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