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authorSteffen Maier <maier@linux.vnet.ibm.com>2012-09-04 15:23:34 +0200
committerJames Bottomley <JBottomley@Parallels.com>2012-09-24 12:11:02 +0400
commitd99b601b63386f3395dc26a699ae703a273d9982 (patch)
tree208966f18e89775d68e82092c1ff648206fbd688 /drivers/s390/scsi
parentca579c9f136af4274ccfd1bcaee7f38a29a0e2e9 (diff)
downloadlinux-d99b601b63386f3395dc26a699ae703a273d9982.tar.bz2
[SCSI] zfcp: restore refcount check on port_remove
Upstream commit f3450c7b917201bb49d67032e9f60d5125675d6a "[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>
Diffstat (limited to 'drivers/s390/scsi')
-rw-r--r--drivers/s390/scsi/zfcp_aux.c1
-rw-r--r--drivers/s390/scsi/zfcp_def.h1
-rw-r--r--drivers/s390/scsi/zfcp_ext.h1
-rw-r--r--drivers/s390/scsi/zfcp_sysfs.c18
-rw-r--r--drivers/s390/scsi/zfcp_unit.c36
5 files changed, 45 insertions, 12 deletions
diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index aff8621de806..f6adde44f226 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -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);
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 5bc4afba8b09..1305955cbf59 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -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 */
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index 4eeef78447f2..03441a7fb463 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -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[];
diff --git a/drivers/s390/scsi/zfcp_sysfs.c b/drivers/s390/scsi/zfcp_sysfs.c
index c66af27b230b..1e0eb089dfba 100644
--- a/drivers/s390/scsi/zfcp_sysfs.c
+++ b/drivers/s390/scsi/zfcp_sysfs.c
@@ -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;
}
diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
index 3f2bff0d3aa2..1cd2b99ab256 100644
--- a/drivers/s390/scsi/zfcp_unit.c
+++ b/drivers/s390/scsi/zfcp_unit.c
@@ -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;
}
/**