Commit d99b601b authored by Steffen Maier's avatar Steffen Maier Committed by James Bottomley
Browse files

[SCSI] zfcp: restore refcount check on port_remove 



Upstream commit f3450c7b
"[SCSI] zfcp: Replace local reference counting with common kref"
accidentally dropped a reference count check before tearing down
zfcp_ports that are potentially in use by zfcp_units.
Even remote ports in use can be removed causing
unreachable garbage objects zfcp_ports with zfcp_units.
Thus units won't come back even after a manual port_rescan.
The kref of zfcp_port->dev.kobj is already used by the driver core.
We cannot re-use it to track the number of zfcp_units.
Re-introduce our own counter for units per port
and check on port_remove.

Signed-off-by: default avatarSteffen Maier <maier@linux.vnet.ibm.com>
Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org> #2.6.33+
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent ca579c9f

drivers/s390/scsi/zfcp_aux.c

+1 −0
Original line number Diff line number Diff line
@@ -519,6 +519,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn, 


	rwlock_init(&port->unit_list_lock);

	INIT_LIST_HEAD(&port->unit_list);

	atomic_set(&port->units, 0);



	INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);

	INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);

drivers/s390/scsi/zfcp_def.h

+1 −0
Original line number Diff line number Diff line
@@ -205,6 +205,7 @@ struct zfcp_port { 
	struct zfcp_adapter    *adapter;       /* adapter used to access port */

	struct list_head	unit_list;	/* head of logical unit list */

	rwlock_t		unit_list_lock; /* unit list lock */

	atomic_t		units;	       /* zfcp_unit count */

	atomic_t	       status;	       /* status of this remote port */

	u64		       wwnn;	       /* WWNN if known */

	u64		       wwpn;	       /* WWPN */

drivers/s390/scsi/zfcp_ext.h

+1 −0
Original line number Diff line number Diff line
@@ -159,6 +159,7 @@ extern void zfcp_scsi_dif_sense_error(struct scsi_cmnd *, int); 
extern struct attribute_group zfcp_sysfs_unit_attrs;

extern struct attribute_group zfcp_sysfs_adapter_attrs;

extern struct attribute_group zfcp_sysfs_port_attrs;

extern struct mutex zfcp_sysfs_port_units_mutex;

extern struct device_attribute *zfcp_sysfs_sdev_attrs[];

extern struct device_attribute *zfcp_sysfs_shost_attrs[];

drivers/s390/scsi/zfcp_sysfs.c

+16 −2
Original line number Diff line number Diff line
@@ -227,6 +227,8 @@ static ssize_t zfcp_sysfs_port_rescan_store(struct device *dev, 
static ZFCP_DEV_ATTR(adapter, port_rescan, S_IWUSR, NULL,

		     zfcp_sysfs_port_rescan_store);



DEFINE_MUTEX(zfcp_sysfs_port_units_mutex);



static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,

					    struct device_attribute *attr,

					    const char *buf, size_t count)
@@ -249,6 +251,16 @@ static ssize_t zfcp_sysfs_port_remove_store(struct device *dev, 
	else

		retval = 0;



	mutex_lock(&zfcp_sysfs_port_units_mutex);

	if (atomic_read(&port->units) > 0) {

		retval = -EBUSY;

		mutex_unlock(&zfcp_sysfs_port_units_mutex);

		goto out;

	}

	/* port is about to be removed, so no more unit_add */

	atomic_set(&port->units, -1);

	mutex_unlock(&zfcp_sysfs_port_units_mutex);



	write_lock_irq(&adapter->port_list_lock);

	list_del(&port->list);

	write_unlock_irq(&adapter->port_list_lock);
@@ -289,12 +301,14 @@ static ssize_t zfcp_sysfs_unit_add_store(struct device *dev, 
{

	struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);

	u64 fcp_lun;

	int retval;



	if (strict_strtoull(buf, 0, (unsigned long long *) &fcp_lun))

		return -EINVAL;



	if (zfcp_unit_add(port, fcp_lun))

		return -EINVAL;

	retval = zfcp_unit_add(port, fcp_lun);

	if (retval)

		return retval;



	return count;

}

drivers/s390/scsi/zfcp_unit.c

+26 −10
Original line number Diff line number Diff line
@@ -104,7 +104,7 @@ static void zfcp_unit_release(struct device *dev) 
{

	struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);



	put_device(&unit->port->dev);

	atomic_dec(&unit->port->units);

	kfree(unit);

}
@@ -119,16 +119,27 @@ static void zfcp_unit_release(struct device *dev) 
int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)

{

	struct zfcp_unit *unit;

	int retval = 0;



	mutex_lock(&zfcp_sysfs_port_units_mutex);

	if (atomic_read(&port->units) == -1) {

		/* port is already gone */

		retval = -ENODEV;

		goto out;

	}



	unit = zfcp_unit_find(port, fcp_lun);

	if (unit) {

		put_device(&unit->dev);

		return -EEXIST;

		retval = -EEXIST;

		goto out;

	}



	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);

	if (!unit)

		return -ENOMEM;

	if (!unit) {

		retval = -ENOMEM;

		goto out;

	}



	unit->port = port;

	unit->fcp_lun = fcp_lun;
@@ -139,28 +150,33 @@ int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun) 
	if (dev_set_name(&unit->dev, "0x%016llx",

			 (unsigned long long) fcp_lun)) {

		kfree(unit);

		return -ENOMEM;

		retval = -ENOMEM;

		goto out;

	}



	get_device(&port->dev);



	if (device_register(&unit->dev)) {

		put_device(&unit->dev);

		return -ENOMEM;

		retval = -ENOMEM;

		goto out;

	}



	if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {

		device_unregister(&unit->dev);

		return -EINVAL;

		retval = -EINVAL;

		goto out;

	}



	atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */



	write_lock_irq(&port->unit_list_lock);

	list_add_tail(&unit->list, &port->unit_list);

	write_unlock_irq(&port->unit_list_lock);



	zfcp_unit_scsi_scan(unit);



	return 0;

out:

	mutex_unlock(&zfcp_sysfs_port_units_mutex);

	return retval;

}



/**

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