From d99b601b63386f3395dc26a699ae703a273d9982 Mon Sep 17 00:00:00 2001 From: Steffen Maier Date: Tue, 4 Sep 2012 15:23:34 +0200 Subject: [PATCH] [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 Reviewed-by: Heiko Carstens Cc: #2.6.33+ Signed-off-by: James Bottomley --- drivers/s390/scsi/zfcp_aux.c | 1 + drivers/s390/scsi/zfcp_def.h | 1 + drivers/s390/scsi/zfcp_ext.h | 1 + drivers/s390/scsi/zfcp_sysfs.c | 18 +++++++++++++++-- drivers/s390/scsi/zfcp_unit.c | 36 ++++++++++++++++++++++++---------- 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; } /** -- 2.20.1