[SCSI] correct transport class abstraction to work outside SCSI

I recently tried to construct a totally generic transport class and
found there were certain features missing from the current abstract
transport class.  Most notable is that you have to hang the data on the
class_device but most of the API is framed in terms of the generic
device, not the class_device.

These changes are two fold

- Provide the class_device to all of the setup and configure APIs
- Provide and extra API to take the device and the attribute class and
  return the corresponding class_device

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/base/attribute_container.c b/drivers/base/attribute_container.c
index ec615d854be9..62c093db11e6 100644
--- a/drivers/base/attribute_container.c
+++ b/drivers/base/attribute_container.c
@@ -58,6 +58,7 @@ attribute_container_register(struct attribute_container *cont)
 {
         INIT_LIST_HEAD(&cont->node);
         INIT_LIST_HEAD(&cont->containers);
+        spin_lock_init(&cont->containers_lock);
                 
         down(&attribute_container_mutex);
         list_add_tail(&cont->node, &attribute_container_list);
@@ -77,11 +78,13 @@ attribute_container_unregister(struct attribute_container *cont)
 {
         int retval = -EBUSY;
         down(&attribute_container_mutex);
+        spin_lock(&cont->containers_lock);
         if (!list_empty(&cont->containers))
                 goto out;
         retval = 0;
         list_del(&cont->node);
  out:
+        spin_unlock(&cont->containers_lock);
         up(&attribute_container_mutex);
         return retval;
                 
@@ -151,7 +154,9 @@ attribute_container_add_device(struct device *dev,
                         fn(cont, dev, &ic->classdev);
                 else
                         attribute_container_add_class_device(&ic->classdev);
+                spin_lock(&cont->containers_lock);
                 list_add_tail(&ic->node, &cont->containers);
+                spin_unlock(&cont->containers_lock);
         }
         up(&attribute_container_mutex);
 }
@@ -189,6 +194,7 @@ attribute_container_remove_device(struct device *dev,
 
                 if (!cont->match(cont, dev))
                         continue;
+                spin_lock(&cont->containers_lock);
                 list_for_each_entry_safe(ic, tmp, &cont->containers, node) {
                         if (dev != ic->classdev.dev)
                                 continue;
@@ -200,6 +206,7 @@ attribute_container_remove_device(struct device *dev,
                                 class_device_unregister(&ic->classdev);
                         }
                 }
+                spin_unlock(&cont->containers_lock);
         }
         up(&attribute_container_mutex);
 }
@@ -230,10 +237,12 @@ attribute_container_device_trigger(struct device *dev,
                 if (!cont->match(cont, dev))
                         continue;
 
+                spin_lock(&cont->containers_lock);
                 list_for_each_entry_safe(ic, tmp, &cont->containers, node) {
                         if (dev == ic->classdev.dev)
                                 fn(cont, dev, &ic->classdev);
                 }
+                spin_unlock(&cont->containers_lock);
         }
         up(&attribute_container_mutex);
 }
@@ -368,6 +377,35 @@ attribute_container_class_device_del(struct class_device *classdev)
 }
 EXPORT_SYMBOL_GPL(attribute_container_class_device_del);
 
+/**
+ * attribute_container_find_class_device - find the corresponding class_device
+ *
+ * @cont:       the container
+ * @dev:        the generic device
+ *
+ * Looks up the device in the container's list of class devices and returns
+ * the corresponding class_device.
+ */
+struct class_device *
+attribute_container_find_class_device(struct attribute_container *cont,
+                                      struct device *dev)
+{
+        struct class_device *cdev = NULL;
+        struct internal_container *ic;
+
+        spin_lock(&cont->containers_lock);
+        list_for_each_entry(ic, &cont->containers, node) {
+                if (ic->classdev.dev == dev) {
+                        cdev = &ic->classdev;
+                        break;
+                }
+        }
+        spin_unlock(&cont->containers_lock);
+
+        return cdev;
+}
+EXPORT_SYMBOL_GPL(attribute_container_find_class_device);
+
 int __init
 attribute_container_init(void)
 {