[SCSI] zfcp: restore refcount check on port_remove
Upstream commit f3450c7b91
"[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: Steffen Maier <maier@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org> #2.6.33+
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
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ca579c9f13
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@ -519,6 +519,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
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rwlock_init(&port->unit_list_lock);
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INIT_LIST_HEAD(&port->unit_list);
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atomic_set(&port->units, 0);
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INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
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INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
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@ -205,6 +205,7 @@ struct zfcp_port {
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struct zfcp_adapter *adapter; /* adapter used to access port */
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struct list_head unit_list; /* head of logical unit list */
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rwlock_t unit_list_lock; /* unit list lock */
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atomic_t units; /* zfcp_unit count */
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atomic_t status; /* status of this remote port */
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u64 wwnn; /* WWNN if known */
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u64 wwpn; /* WWPN */
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@ -159,6 +159,7 @@ extern void zfcp_scsi_dif_sense_error(struct scsi_cmnd *, int);
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extern struct attribute_group zfcp_sysfs_unit_attrs;
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extern struct attribute_group zfcp_sysfs_adapter_attrs;
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extern struct attribute_group zfcp_sysfs_port_attrs;
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extern struct mutex zfcp_sysfs_port_units_mutex;
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extern struct device_attribute *zfcp_sysfs_sdev_attrs[];
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extern struct device_attribute *zfcp_sysfs_shost_attrs[];
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@ -227,6 +227,8 @@ static ssize_t zfcp_sysfs_port_rescan_store(struct device *dev,
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static ZFCP_DEV_ATTR(adapter, port_rescan, S_IWUSR, NULL,
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zfcp_sysfs_port_rescan_store);
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DEFINE_MUTEX(zfcp_sysfs_port_units_mutex);
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static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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@ -249,6 +251,16 @@ static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
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else
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retval = 0;
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mutex_lock(&zfcp_sysfs_port_units_mutex);
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if (atomic_read(&port->units) > 0) {
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retval = -EBUSY;
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mutex_unlock(&zfcp_sysfs_port_units_mutex);
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goto out;
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}
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/* port is about to be removed, so no more unit_add */
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atomic_set(&port->units, -1);
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mutex_unlock(&zfcp_sysfs_port_units_mutex);
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write_lock_irq(&adapter->port_list_lock);
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list_del(&port->list);
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write_unlock_irq(&adapter->port_list_lock);
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@ -289,12 +301,14 @@ static ssize_t zfcp_sysfs_unit_add_store(struct device *dev,
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{
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struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);
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u64 fcp_lun;
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int retval;
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if (strict_strtoull(buf, 0, (unsigned long long *) &fcp_lun))
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return -EINVAL;
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if (zfcp_unit_add(port, fcp_lun))
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return -EINVAL;
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retval = zfcp_unit_add(port, fcp_lun);
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if (retval)
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return retval;
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return count;
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}
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@ -104,7 +104,7 @@ static void zfcp_unit_release(struct device *dev)
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{
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struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
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put_device(&unit->port->dev);
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atomic_dec(&unit->port->units);
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kfree(unit);
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}
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@ -119,16 +119,27 @@ static void zfcp_unit_release(struct device *dev)
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int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
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{
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struct zfcp_unit *unit;
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int retval = 0;
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mutex_lock(&zfcp_sysfs_port_units_mutex);
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if (atomic_read(&port->units) == -1) {
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/* port is already gone */
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retval = -ENODEV;
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goto out;
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}
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unit = zfcp_unit_find(port, fcp_lun);
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if (unit) {
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put_device(&unit->dev);
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return -EEXIST;
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retval = -EEXIST;
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goto out;
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}
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unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
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if (!unit)
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return -ENOMEM;
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if (!unit) {
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retval = -ENOMEM;
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goto out;
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}
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unit->port = port;
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unit->fcp_lun = fcp_lun;
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@ -139,28 +150,33 @@ int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
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if (dev_set_name(&unit->dev, "0x%016llx",
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(unsigned long long) fcp_lun)) {
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kfree(unit);
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return -ENOMEM;
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retval = -ENOMEM;
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goto out;
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}
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get_device(&port->dev);
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if (device_register(&unit->dev)) {
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put_device(&unit->dev);
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return -ENOMEM;
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retval = -ENOMEM;
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goto out;
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}
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if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
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device_unregister(&unit->dev);
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return -EINVAL;
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retval = -EINVAL;
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goto out;
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}
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atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */
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write_lock_irq(&port->unit_list_lock);
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list_add_tail(&unit->list, &port->unit_list);
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write_unlock_irq(&port->unit_list_lock);
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zfcp_unit_scsi_scan(unit);
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return 0;
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out:
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mutex_unlock(&zfcp_sysfs_port_units_mutex);
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return retval;
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}
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/**
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