zfcp: trace on request for open and close of WKA port

[pandora-kernel.git] / drivers / s390 / scsi / zfcp_sysfs.c

diff --git a/drivers/s390/scsi/zfcp_sysfs.c b/drivers/s390/scsi/zfcp_sysfs.c
index cdc4ff7..9e62210 100644 (file)
--- 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;
 }