Commit e4a9c373 authored by Dan Williams's avatar Dan Williams Committed by James Bottomley
Browse files

[SCSI] libata, libsas: introduce sched_eh and end_eh port ops 



When managing shost->host_eh_scheduled libata assumes that there is a
1:1 shost-to-ata_port relationship.  libsas creates a 1:N relationship
so it needs to manage host_eh_scheduled cumulatively at the host level.
The sched_eh and end_eh port port ops allow libsas to track when domain
devices enter/leave the "eh-pending" state under ha->lock (previously
named ha->state_lock, but it is no longer just a lock for ha->state
changes).

Since host_eh_scheduled indicates eh without backing commands pinning
the device it can be deallocated at any time.  Move the taking of the
domain_device reference under the port_lock to guarantee that the
ata_port stays around for the duration of eh.

Reviewed-by: default avatarJacek Danecki <jacek.danecki@intel.com>
Acked-by: default avatarJeff Garzik <jgarzik@redhat.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 3b661a92

drivers/ata/libata-core.c

+4 −0
Original line number Diff line number Diff line
@@ -80,6 +80,8 @@ const struct ata_port_operations ata_base_port_ops = { 
	.prereset		= ata_std_prereset,

	.postreset		= ata_std_postreset,

	.error_handler		= ata_std_error_handler,

	.sched_eh		= ata_std_sched_eh,

	.end_eh			= ata_std_end_eh,

};



const struct ata_port_operations sata_port_ops = {
@@ -6642,6 +6644,8 @@ struct ata_port_operations ata_dummy_port_ops = { 
	.qc_prep		= ata_noop_qc_prep,

	.qc_issue		= ata_dummy_qc_issue,

	.error_handler		= ata_dummy_error_handler,

	.sched_eh		= ata_std_sched_eh,

	.end_eh			= ata_std_end_eh,

};



const struct ata_port_info ata_dummy_port_info = {

drivers/ata/libata-eh.c

+46 −11
Original line number Diff line number Diff line
@@ -793,12 +793,12 @@ void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap) 
		ata_for_each_link(link, ap, HOST_FIRST)

			memset(&link->eh_info, 0, sizeof(link->eh_info));



		/* Clear host_eh_scheduled while holding ap->lock such

		 * that if exception occurs after this point but

		 * before EH completion, SCSI midlayer will

		/* end eh (clear host_eh_scheduled) while holding

		 * ap->lock such that if exception occurs after this

		 * point but before EH completion, SCSI midlayer will

		 * re-initiate EH.

		 */

		host->host_eh_scheduled = 0;

		ap->ops->end_eh(ap);



		spin_unlock_irqrestore(ap->lock, flags);

		ata_eh_release(ap);
@@ -986,16 +986,13 @@ void ata_qc_schedule_eh(struct ata_queued_cmd *qc) 
}



/**

 *	ata_port_schedule_eh - schedule error handling without a qc

 * ata_std_sched_eh - non-libsas ata_ports issue eh with this common routine

 * @ap: ATA port to schedule EH for

 *

 *	Schedule error handling for @ap.  EH will kick in as soon as

 *	all commands are drained.

 *

 *	LOCKING:

 *	LOCKING: inherited from ata_port_schedule_eh

 *	spin_lock_irqsave(host lock)

 */

void ata_port_schedule_eh(struct ata_port *ap)

void ata_std_sched_eh(struct ata_port *ap)

{

	WARN_ON(!ap->ops->error_handler);
@@ -1007,6 +1004,44 @@ void ata_port_schedule_eh(struct ata_port *ap) 


	DPRINTK("port EH scheduled\n");

}

EXPORT_SYMBOL_GPL(ata_std_sched_eh);



/**

 * ata_std_end_eh - non-libsas ata_ports complete eh with this common routine

 * @ap: ATA port to end EH for

 *

 * In the libata object model there is a 1:1 mapping of ata_port to

 * shost, so host fields can be directly manipulated under ap->lock, in

 * the libsas case we need to hold a lock at the ha->level to coordinate

 * these events.

 *

 *	LOCKING:

 *	spin_lock_irqsave(host lock)

 */

void ata_std_end_eh(struct ata_port *ap)

{

	struct Scsi_Host *host = ap->scsi_host;



	host->host_eh_scheduled = 0;

}

EXPORT_SYMBOL(ata_std_end_eh);





/**

 *	ata_port_schedule_eh - schedule error handling without a qc

 *	@ap: ATA port to schedule EH for

 *

 *	Schedule error handling for @ap.  EH will kick in as soon as

 *	all commands are drained.

 *

 *	LOCKING:

 *	spin_lock_irqsave(host lock)

 */

void ata_port_schedule_eh(struct ata_port *ap)

{

	/* see: ata_std_sched_eh, unless you know better */

	ap->ops->sched_eh(ap);

}



static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)

{

drivers/scsi/libsas/sas_ata.c

+34 −4
Original line number Diff line number Diff line
@@ -523,6 +523,31 @@ static void sas_ata_set_dmamode(struct ata_port *ap, struct ata_device *ata_dev) 
		i->dft->lldd_ata_set_dmamode(dev);

}



static void sas_ata_sched_eh(struct ata_port *ap)

{

	struct domain_device *dev = ap->private_data;

	struct sas_ha_struct *ha = dev->port->ha;

	unsigned long flags;



	spin_lock_irqsave(&ha->lock, flags);

	if (!test_and_set_bit(SAS_DEV_EH_PENDING, &dev->state))

		ha->eh_active++;

	ata_std_sched_eh(ap);

	spin_unlock_irqrestore(&ha->lock, flags);

}



void sas_ata_end_eh(struct ata_port *ap)

{

	struct domain_device *dev = ap->private_data;

	struct sas_ha_struct *ha = dev->port->ha;

	unsigned long flags;



	spin_lock_irqsave(&ha->lock, flags);

	if (test_and_clear_bit(SAS_DEV_EH_PENDING, &dev->state))

		ha->eh_active--;

	spin_unlock_irqrestore(&ha->lock, flags);

}



static struct ata_port_operations sas_sata_ops = {

	.prereset		= ata_std_prereset,

	.hardreset		= sas_ata_hard_reset,
@@ -536,6 +561,8 @@ static struct ata_port_operations sas_sata_ops = { 
	.port_start		= ata_sas_port_start,

	.port_stop		= ata_sas_port_stop,

	.set_dmamode		= sas_ata_set_dmamode,

	.sched_eh		= sas_ata_sched_eh,

	.end_eh			= sas_ata_end_eh,

};



static struct ata_port_info sata_port_info = {
@@ -708,10 +735,6 @@ static void async_sas_ata_eh(void *data, async_cookie_t cookie) 
	struct ata_port *ap = dev->sata_dev.ap;

	struct sas_ha_struct *ha = dev->port->ha;



	/* hold a reference over eh since we may be racing with final

	 * remove once all commands are completed

	 */

	kref_get(&dev->kref);

	sas_ata_printk(KERN_DEBUG, dev, "dev error handler\n");

	ata_scsi_port_error_handler(ha->core.shost, ap);

	sas_put_device(dev);
@@ -742,6 +765,13 @@ void sas_ata_strategy_handler(struct Scsi_Host *shost) 
		list_for_each_entry(dev, &port->dev_list, dev_list_node) {

			if (!dev_is_sata(dev))

				continue;



			/* hold a reference over eh since we may be

			 * racing with final remove once all commands

			 * are completed

			 */

			kref_get(&dev->kref);



			async_schedule_domain(async_sas_ata_eh, dev, &async);

		}

		spin_unlock(&port->dev_list_lock);

drivers/scsi/libsas/sas_discover.c

+4 −2
Original line number Diff line number Diff line
@@ -294,6 +294,8 @@ static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_d 


	spin_lock_irq(&port->dev_list_lock);

	list_del_init(&dev->dev_list_node);

	if (dev_is_sata(dev))

		sas_ata_end_eh(dev->sata_dev.ap);

	spin_unlock_irq(&port->dev_list_lock);



	sas_put_device(dev);
@@ -488,9 +490,9 @@ static void sas_chain_event(int event, unsigned long *pending, 
	if (!test_and_set_bit(event, pending)) {

		unsigned long flags;



		spin_lock_irqsave(&ha->state_lock, flags);

		spin_lock_irqsave(&ha->lock, flags);

		sas_chain_work(ha, sw);

		spin_unlock_irqrestore(&ha->state_lock, flags);

		spin_unlock_irqrestore(&ha->lock, flags);

	}

}

drivers/scsi/libsas/sas_event.c

+6 −6
Original line number Diff line number Diff line
@@ -47,9 +47,9 @@ static void sas_queue_event(int event, unsigned long *pending, 
	if (!test_and_set_bit(event, pending)) {

		unsigned long flags;



		spin_lock_irqsave(&ha->state_lock, flags);

		spin_lock_irqsave(&ha->lock, flags);

		sas_queue_work(ha, work);

		spin_unlock_irqrestore(&ha->state_lock, flags);

		spin_unlock_irqrestore(&ha->lock, flags);

	}

}
@@ -61,18 +61,18 @@ void __sas_drain_work(struct sas_ha_struct *ha) 


	set_bit(SAS_HA_DRAINING, &ha->state);

	/* flush submitters */

	spin_lock_irq(&ha->state_lock);

	spin_unlock_irq(&ha->state_lock);

	spin_lock_irq(&ha->lock);

	spin_unlock_irq(&ha->lock);



	drain_workqueue(wq);



	spin_lock_irq(&ha->state_lock);

	spin_lock_irq(&ha->lock);

	clear_bit(SAS_HA_DRAINING, &ha->state);

	list_for_each_entry_safe(sw, _sw, &ha->defer_q, drain_node) {

		list_del_init(&sw->drain_node);

		sas_queue_work(ha, sw);

	}

	spin_unlock_irq(&ha->state_lock);

	spin_unlock_irq(&ha->lock);

}



int sas_drain_work(struct sas_ha_struct *ha)

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