From: Christof Schmitt Date: Wed, 8 Sep 2010 12:39:54 +0000 (+0200) Subject: [SCSI] zfcp: Allow running unit/LUN shutdown without acquiring reference X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=fdbd1c5e27da;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git [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: Swen Schillig Signed-off-by: Christof Schmitt Signed-off-by: James Bottomley --- diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c index 160b432c907f..50514b4c8732 100644 --- a/drivers/s390/scsi/zfcp_erp.c +++ b/drivers/s390/scsi/zfcp_erp.c @@ -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 (!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_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; @@ -1191,7 +1216,8 @@ static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result) 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 --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h index 5c3966eaca51..3c90604076e0 100644 --- a/drivers/s390/scsi/zfcp_ext.h +++ b/drivers/s390/scsi/zfcp_ext.h @@ -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 *);