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Commit 6f63caae authored by Darrick J. Wong's avatar Darrick J. Wong Committed by James Bottomley
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[SCSI] libsas: Clean up discovery failure handler code 



sas_rphy_delete does two things: it removes the sas_rphy from the transport
layer and frees the sas_rphy.  This can be broken down into two functions,
sas_rphy_remove and sas_rphy_free; sas_rphy_remove is of interest to
sas_discover_root_expander because it calls functions that require
sas_rphy_add as a prerequisite and can fail (namely sas_discover_expander).
In that case, sas_discover_root_expander needs to be able to undo the effects
of sas_rphy_add yet leave the job of freeing the sas_rphy to the caller of
sas_discover_root_expander.

This patch also removes some unnecessary code from sas_discover_end_dev
to eliminate an unnecessary cycle of sas_notify_lldd_gone/found for SAS
devices, thus eliminating a sas_rphy_remove call (and fixing a race condition
where a SCSI target scan can come in between the gone and found call).
It also moves the sas_rphy_free calls into sas_discover_domain and
sas_ex_discover_end_dev to complement the sas_rphy_allocation via
sas_get_port_device.

This patch does not change the semantics of sas_rphy_delete.

Signed-off-by: default avatarDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 3b6e9faf

drivers/scsi/libsas/sas_discover.c

+17 −28
Original line number Diff line number Diff line
@@ -577,8 +577,6 @@ int sas_discover_sata(struct domain_device *dev) 
out_err:

	sas_notify_lldd_dev_gone(dev);

out_err2:

	sas_rphy_free(dev->rphy);

	dev->rphy = NULL;

	return res;

}
@@ -600,24 +598,11 @@ int sas_discover_end_dev(struct domain_device *dev) 
	if (res)

		goto out_err;



	/* do this to get the end device port attributes which will have

	 * been scanned in sas_rphy_add */

	sas_notify_lldd_dev_gone(dev);

	res = sas_notify_lldd_dev_found(dev);

	if (res)

		goto out_err3;



	return 0;



out_err:

	sas_notify_lldd_dev_gone(dev);

out_err2:

	sas_rphy_free(dev->rphy);

	dev->rphy = NULL;

	return res;

out_err3:

	sas_rphy_delete(dev->rphy);

	dev->rphy = NULL;

	return res;

}
@@ -672,6 +657,7 @@ void sas_unregister_domain_devices(struct asd_sas_port *port) 
 */

static void sas_discover_domain(struct work_struct *work)

{

	struct domain_device *dev;

	int error = 0;

	struct sas_discovery_event *ev =

		container_of(work, struct sas_discovery_event, work);
@@ -682,38 +668,41 @@ static void sas_discover_domain(struct work_struct *work) 


	if (port->port_dev)

		return;

	else {



	error = sas_get_port_device(port);

	if (error)

		return;

	}

	dev = port->port_dev;



	SAS_DPRINTK("DOING DISCOVERY on port %d, pid:%d\n", port->id,

		    current->pid);



	switch (port->port_dev->dev_type) {

	switch (dev->dev_type) {

	case SAS_END_DEV:

		error = sas_discover_end_dev(port->port_dev);

		error = sas_discover_end_dev(dev);

		break;

	case EDGE_DEV:

	case FANOUT_DEV:

		error = sas_discover_root_expander(port->port_dev);

		error = sas_discover_root_expander(dev);

		break;

	case SATA_DEV:

	case SATA_PM:

		error = sas_discover_sata(port->port_dev);

		error = sas_discover_sata(dev);

		break;

	default:

		SAS_DPRINTK("unhandled device %d\n", port->port_dev->dev_type);

		SAS_DPRINTK("unhandled device %d\n", dev->dev_type);

		break;

	}



	if (error) {

		sas_rphy_free(dev->rphy);

		dev->rphy = NULL;



		spin_lock(&port->dev_list_lock);

		list_del_init(&port->port_dev->dev_list_node);

		list_del_init(&dev->dev_list_node);

		spin_unlock(&port->dev_list_lock);



		kfree(port->port_dev); /* not kobject_register-ed yet */

		kfree(dev); /* not kobject_register-ed yet */

		port->port_dev = NULL;

	}

drivers/scsi/libsas/sas_expander.c

+3 −5
Original line number Diff line number Diff line
@@ -667,6 +667,8 @@ static struct domain_device *sas_ex_discover_end_dev( 
	return child;



 out_list_del:

	sas_rphy_free(child->rphy);

	child->rphy = NULL;

	list_del(&child->dev_list_node);

 out_free:

	sas_port_delete(phy->port);
@@ -1444,12 +1446,8 @@ int sas_discover_root_expander(struct domain_device *dev) 
	return res;



out_err2:

	sas_rphy_delete(dev->rphy);

	dev->rphy = NULL;

	return res;

	sas_rphy_remove(dev->rphy);

out_err:

	sas_rphy_free(dev->rphy);

	dev->rphy = NULL;

	return res;

}

drivers/scsi/scsi_transport_sas.c

+19 −14
Original line number Diff line number Diff line
@@ -1299,7 +1299,7 @@ EXPORT_SYMBOL(sas_rphy_add); 
 * Note:

 *   This function must only be called on a remote

 *   PHY that has not sucessfully been added using

 *   sas_rphy_add().

 *   sas_rphy_add() (or has been sas_rphy_remove()'d)

 */

void sas_rphy_free(struct sas_rphy *rphy)

{
@@ -1318,18 +1318,30 @@ void sas_rphy_free(struct sas_rphy *rphy) 
EXPORT_SYMBOL(sas_rphy_free);



/**

 * sas_rphy_delete  --  remove SAS remote PHY

 * @rphy:	SAS remote PHY to remove

 * sas_rphy_delete  --  remove and free SAS remote PHY

 * @rphy:	SAS remote PHY to remove and free

 *

 * Removes the specified SAS remote PHY.

 * Removes the specified SAS remote PHY and frees it.

 */

void

sas_rphy_delete(struct sas_rphy *rphy)

{

	sas_rphy_remove(rphy);

	sas_rphy_free(rphy);

}

EXPORT_SYMBOL(sas_rphy_delete);



/**

 * sas_rphy_remove  --  remove SAS remote PHY

 * @rphy:	SAS remote phy to remove

 *

 * Removes the specified SAS remote PHY.

 */

void

sas_rphy_remove(struct sas_rphy *rphy)

{

	struct device *dev = &rphy->dev;

	struct sas_port *parent = dev_to_sas_port(dev->parent);

	struct Scsi_Host *shost = dev_to_shost(parent->dev.parent);

	struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);



	switch (rphy->identify.device_type) {

	case SAS_END_DEVICE:
@@ -1345,17 +1357,10 @@ sas_rphy_delete(struct sas_rphy *rphy) 


	transport_remove_device(dev);

	device_del(dev);

	transport_destroy_device(dev);



	mutex_lock(&sas_host->lock);

	list_del(&rphy->list);

	mutex_unlock(&sas_host->lock);



	parent->rphy = NULL;



	put_device(dev);

}

EXPORT_SYMBOL(sas_rphy_delete);

EXPORT_SYMBOL(sas_rphy_remove);



/**

 * scsi_is_sas_rphy  --  check if a struct device represents a SAS remote PHY

include/scsi/scsi_transport_sas.h

+1 −0
Original line number Diff line number Diff line
@@ -182,6 +182,7 @@ extern struct sas_rphy *sas_end_device_alloc(struct sas_port *); 
extern struct sas_rphy *sas_expander_alloc(struct sas_port *, enum sas_device_type);

void sas_rphy_free(struct sas_rphy *);

extern int sas_rphy_add(struct sas_rphy *);

extern void sas_rphy_remove(struct sas_rphy *);

extern void sas_rphy_delete(struct sas_rphy *);

extern int scsi_is_sas_rphy(const struct device *);