[IB] Fail sysfs queries after device is unregistered

We keep IB device structures around until the last sysfs reference is
gone, but we shouldn't ask the low-level driver to do anything after
the LLD unregisters the device.  To handle this, check the reg_state
field and just fail sysfs show() requests if the device has already
been unregistered.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/infiniband/core/sysfs.c b/drivers/infiniband/core/sysfs.c
index 211ba3223f65..7ce7a6c782fa 100644
--- a/drivers/infiniband/core/sysfs.c
+++ b/drivers/infiniband/core/sysfs.c
@@ -65,6 +65,11 @@ struct port_table_attribute {
         int                     index;
 };
 
+static inline int ibdev_is_alive(const struct ib_device *dev) 
+{
+        return dev->reg_state == IB_DEV_REGISTERED;
+}
+
 static ssize_t port_attr_show(struct kobject *kobj,
                               struct attribute *attr, char *buf)
 {
@@ -74,6 +79,8 @@ static ssize_t port_attr_show(struct kobject *kobj,
 
         if (!port_attr->show)
                 return -EIO;
+        if (!ibdev_is_alive(p->ibdev))
+                return -ENODEV;
 
         return port_attr->show(p, port_attr, buf);
 }
@@ -581,6 +588,9 @@ static ssize_t show_node_type(struct class_device *cdev, char *buf)
 {
         struct ib_device *dev = container_of(cdev, struct ib_device, class_dev);
 
+        if (!ibdev_is_alive(dev))
+                return -ENODEV;
+
         switch (dev->node_type) {
         case IB_NODE_CA:     return sprintf(buf, "%d: CA\n", dev->node_type);
         case IB_NODE_SWITCH: return sprintf(buf, "%d: switch\n", dev->node_type);
@@ -595,6 +605,9 @@ static ssize_t show_sys_image_guid(struct class_device *cdev, char *buf)
         struct ib_device_attr attr;
         ssize_t ret;
 
+        if (!ibdev_is_alive(dev))
+                return -ENODEV;
+
         ret = ib_query_device(dev, &attr);
         if (ret)
                 return ret;
@@ -612,6 +625,9 @@ static ssize_t show_node_guid(struct class_device *cdev, char *buf)
         struct ib_device_attr attr;
         ssize_t ret;
 
+        if (!ibdev_is_alive(dev))
+                return -ENODEV;
+
         ret = ib_query_device(dev, &attr);
         if (ret)
                 return ret;