EDAC: Export edac sysfs class to users.

Move toplevel sysfs class to the stub and make it available to
non-modularized code too. Add proper refcounting of its users and move
the registration functionality into the reference counting routines.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

7 files changed, 75 insertions, 95 deletions

diff --git a/drivers/edac/edac_device_sysfs.c b/drivers/edac/edac_device_sysfs.c
index 070968178a24..2941dca91aae 100644
--- a/drivers/edac/edac_device_sysfs.c
+++ b/drivers/edac/edac_device_sysfs.c
@@ -13,6 +13,7 @@
 #include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/edac.h>
 
 #include "edac_core.h"
 #include "edac_module.h"
@@ -235,7 +236,7 @@ int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
         debugf1("%s()\n", __func__);
 
         /* get the /sys/devices/system/edac reference */
-        edac_class = edac_get_edac_class();
+        edac_class = edac_get_sysfs_class();
         if (edac_class == NULL) {
                 debugf1("%s() no edac_class error\n", __func__);
                 err = -ENODEV;
@@ -255,7 +256,7 @@ int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
 
         if (!try_module_get(edac_dev->owner)) {
                 err = -ENODEV;
-                goto err_out;
+                goto err_mod_get;
         }
 
         /* register */
@@ -282,6 +283,9 @@ int edac_device_register_sysfs_main_kobj(struct edac_device_ctl_info *edac_dev)
 err_kobj_reg:
         module_put(edac_dev->owner);
 
+err_mod_get:
+        edac_put_sysfs_class();
+
 err_out:
         return err;
 }
@@ -290,12 +294,11 @@ err_out:
  * edac_device_unregister_sysfs_main_kobj:
  *      the '..../edac/<name>' kobject
  */
-void edac_device_unregister_sysfs_main_kobj(
-                                        struct edac_device_ctl_info *edac_dev)
+void edac_device_unregister_sysfs_main_kobj(struct edac_device_ctl_info *dev)
 {
         debugf0("%s()\n", __func__);
         debugf4("%s() name of kobject is: %s\n",
-                __func__, kobject_name(&edac_dev->kobj));
+                __func__, kobject_name(&dev->kobj));
 
         /*
          * Unregister the edac device's kobject and
@@ -304,7 +307,8 @@ void edac_device_unregister_sysfs_main_kobj(
          *   a) module_put() this module
          *   b) 'kfree' the memory
          */
-        kobject_put(&edac_dev->kobj);
+        kobject_put(&dev->kobj);
+        edac_put_sysfs_class();
 }
 
 /* edac_dev -> instance information */
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index aa93ad82ee07..a4135860149b 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -11,6 +11,7 @@
 
 #include <linux/ctype.h>
 #include <linux/slab.h>
+#include <linux/edac.h>
 #include <linux/bug.h>
 
 #include "edac_core.h"
@@ -1017,7 +1018,7 @@ int edac_sysfs_setup_mc_kset(void)
         debugf1("%s()\n", __func__);
 
         /* get the /sys/devices/system/edac class reference */
-        edac_class = edac_get_edac_class();
+        edac_class = edac_get_sysfs_class();
         if (edac_class == NULL) {
                 debugf1("%s() no edac_class error=%d\n", __func__, err);
                 goto fail_out;
@@ -1028,15 +1029,16 @@ int edac_sysfs_setup_mc_kset(void)
         if (!mc_kset) {
                 err = -ENOMEM;
                 debugf1("%s() Failed to register '.../edac/mc'\n", __func__);
-                goto fail_out;
+                goto fail_kset;
         }
 
         debugf1("%s() Registered '.../edac/mc' kobject\n", __func__);
 
         return 0;
 
+fail_kset:
+        edac_put_sysfs_class();
 
-        /* error unwind stack */
 fail_out:
         return err;
 }
@@ -1049,5 +1051,6 @@ fail_out:
 void edac_sysfs_teardown_mc_kset(void)
 {
         kset_unregister(mc_kset);
+        edac_put_sysfs_class();
 }
 
diff --git a/drivers/edac/edac_module.c b/drivers/edac/edac_module.c
index 7e1374afd967..be4b075c3098 100644
--- a/drivers/edac/edac_module.c
+++ b/drivers/edac/edac_module.c
@@ -27,15 +27,6 @@ EXPORT_SYMBOL_GPL(edac_debug_level);
 struct workqueue_struct *edac_workqueue;
 
 /*
- * sysfs object: /sys/devices/system/edac
- *      need to export to other files in this modules
- */
-static struct sysdev_class edac_class = {
-        .name = "edac",
-};
-static int edac_class_valid;
-
-/*
  * edac_op_state_to_string()
  */
 char *edac_op_state_to_string(int opstate)
@@ -55,60 +46,6 @@ char *edac_op_state_to_string(int opstate)
 }
 
 /*
- * edac_get_edac_class()
- *
- *      return pointer to the edac class of 'edac'
- */
-struct sysdev_class *edac_get_edac_class(void)
-{
-        struct sysdev_class *classptr = NULL;
-
-        if (edac_class_valid)
-                classptr = &edac_class;
-
-        return classptr;
-}
-
-/*
- * edac_register_sysfs_edac_name()
- *
- *      register the 'edac' into /sys/devices/system
- *
- * return:
- *      0  success
- *      !0 error
- */
-static int edac_register_sysfs_edac_name(void)
-{
-        int err;
-
-        /* create the /sys/devices/system/edac directory */
-        err = sysdev_class_register(&edac_class);
-
-        if (err) {
-                debugf1("%s() error=%d\n", __func__, err);
-                return err;
-        }
-
-        edac_class_valid = 1;
-        return 0;
-}
-
-/*
- * sysdev_class_unregister()
- *
- *      unregister the 'edac' from /sys/devices/system
- */
-static void edac_unregister_sysfs_edac_name(void)
-{
-        /* only if currently registered, then unregister it */
-        if (edac_class_valid)
-                sysdev_class_unregister(&edac_class);
-
-        edac_class_valid = 0;
-}
-
-/*
  * edac_workqueue_setup
  *      initialize the edac work queue for polling operations
  */
@@ -154,21 +91,11 @@ static int __init edac_init(void)
         edac_pci_clear_parity_errors();
 
         /*
-         * perform the registration of the /sys/devices/system/edac class object
-         */
-        if (edac_register_sysfs_edac_name()) {
-                edac_printk(KERN_ERR, EDAC_MC,
-                        "Error initializing 'edac' kobject\n");
-                err = -ENODEV;
-                goto error;
-        }
-
-        /*
          * now set up the mc_kset under the edac class object
          */
         err = edac_sysfs_setup_mc_kset();
         if (err)
-                goto sysfs_setup_fail;
+                goto error;
 
         /* Setup/Initialize the workq for this core */
         err = edac_workqueue_setup();
@@ -183,9 +110,6 @@ static int __init edac_init(void)
 workq_fail:
         edac_sysfs_teardown_mc_kset();
 
-sysfs_setup_fail:
-        edac_unregister_sysfs_edac_name();
-
 error:
         return err;
 }
@@ -201,7 +125,6 @@ static void __exit edac_exit(void)
         /* tear down the various subsystems */
         edac_workqueue_teardown();
         edac_sysfs_teardown_mc_kset();
-        edac_unregister_sysfs_edac_name();
 }
 
 /*
diff --git a/drivers/edac/edac_module.h b/drivers/edac/edac_module.h
index 233d4798c3aa..17aabb7b90ec 100644
--- a/drivers/edac/edac_module.h
+++ b/drivers/edac/edac_module.h
@@ -42,7 +42,6 @@ extern void edac_device_unregister_sysfs_main_kobj(
                                 struct edac_device_ctl_info *edac_dev);
 extern int edac_device_create_sysfs(struct edac_device_ctl_info *edac_dev);
 extern void edac_device_remove_sysfs(struct edac_device_ctl_info *edac_dev);
-extern struct sysdev_class *edac_get_edac_class(void);
 
 /* edac core workqueue: single CPU mode */
 extern struct workqueue_struct *edac_workqueue;
diff --git a/drivers/edac/edac_pci_sysfs.c b/drivers/edac/edac_pci_sysfs.c
index c39697df9cb4..023b01cb5175 100644
--- a/drivers/edac/edac_pci_sysfs.c
+++ b/drivers/edac/edac_pci_sysfs.c
@@ -7,7 +7,7 @@
  *
  */
 #include <linux/module.h>
-#include <linux/sysdev.h>
+#include <linux/edac.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
 
@@ -354,7 +354,7 @@ static int edac_pci_main_kobj_setup(void)
         /* First time, so create the main kobject and its
          * controls and atributes
          */
-        edac_class = edac_get_edac_class();
+        edac_class = edac_get_sysfs_class();
         if (edac_class == NULL) {
                 debugf1("%s() no edac_class\n", __func__);
                 err = -ENODEV;
@@ -368,7 +368,7 @@ static int edac_pci_main_kobj_setup(void)
         if (!try_module_get(THIS_MODULE)) {
                 debugf1("%s() try_module_get() failed\n", __func__);
                 err = -ENODEV;
-                goto decrement_count_fail;
+                goto mod_get_fail;
         }
 
         edac_pci_top_main_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
@@ -403,6 +403,9 @@ kobject_init_and_add_fail:
 kzalloc_fail:
         module_put(THIS_MODULE);
 
+mod_get_fail:
+        edac_put_sysfs_class();
+
 decrement_count_fail:
         /* if are on this error exit, nothing to tear down */
         atomic_dec(&edac_pci_sysfs_refcount);
@@ -429,6 +432,7 @@ static void edac_pci_main_kobj_teardown(void)
                         __func__);
                 kobject_put(edac_pci_top_main_kobj);
         }
+        edac_put_sysfs_class();
 }
 
 /*
diff --git a/drivers/edac/edac_stub.c b/drivers/edac/edac_stub.c
index 20b428aa155e..aab970760b75 100644
--- a/drivers/edac/edac_stub.c
+++ b/drivers/edac/edac_stub.c
@@ -3,10 +3,13 @@
  *
  * Author: Dave Jiang <djiang@mvista.com>
  *
- * 2007 (c) MontaVista Software, Inc. This file is licensed under
- * the terms of the GNU General Public License version 2. This program
- * is licensed "as is" without any warranty of any kind, whether express
- * or implied.
+ * 2007 (c) MontaVista Software, Inc.
+ * 2010 (c) Advanced Micro Devices Inc.
+ *          Borislav Petkov <borislav.petkov@amd.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
  *
  */
 #include <linux/module.h>
@@ -23,6 +26,8 @@ EXPORT_SYMBOL_GPL(edac_handlers);
 int edac_err_assert = 0;
 EXPORT_SYMBOL_GPL(edac_err_assert);
 
+static atomic_t edac_class_valid = ATOMIC_INIT(0);
+
 /*
  * called to determine if there is an EDAC driver interested in
  * knowing an event (such as NMI) occurred
@@ -44,3 +49,41 @@ void edac_atomic_assert_error(void)
         edac_err_assert++;
 }
 EXPORT_SYMBOL_GPL(edac_atomic_assert_error);
+
+/*
+ * sysfs object: /sys/devices/system/edac
+ *      need to export to other files
+ */
+struct sysdev_class edac_class = {
+        .name = "edac",
+};
+EXPORT_SYMBOL_GPL(edac_class);
+
+/* return pointer to the 'edac' node in sysfs */
+struct sysdev_class *edac_get_sysfs_class(void)
+{
+        int err = 0;
+
+        if (atomic_read(&edac_class_valid))
+                goto out;
+
+        /* create the /sys/devices/system/edac directory */
+        err = sysdev_class_register(&edac_class);
+        if (err) {
+                printk(KERN_ERR "Error registering toplevel EDAC sysfs dir\n");
+                return NULL;
+        }
+
+out:
+        atomic_inc(&edac_class_valid);
+        return &edac_class;
+}
+EXPORT_SYMBOL_GPL(edac_get_sysfs_class);
+
+void edac_put_sysfs_class(void)
+{
+        /* last user unregisters it */
+        if (atomic_dec_and_test(&edac_class_valid))
+                sysdev_class_unregister(&edac_class);
+}
+EXPORT_SYMBOL_GPL(edac_put_sysfs_class);
diff --git a/include/linux/edac.h b/include/linux/edac.h
index 7cf92e8a4196..36c66443bdfd 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -13,6 +13,7 @@
 #define _LINUX_EDAC_H_
 
 #include <asm/atomic.h>
+#include <linux/sysdev.h>
 
 #define EDAC_OPSTATE_INVAL      -1
 #define EDAC_OPSTATE_POLL       0
@@ -22,9 +23,12 @@
 extern int edac_op_state;
 extern int edac_err_assert;
 extern atomic_t edac_handlers;
+extern struct sysdev_class edac_class;
 
 extern int edac_handler_set(void);
 extern void edac_atomic_assert_error(void);
+extern struct sysdev_class *edac_get_sysfs_class(void);
+extern void edac_put_sysfs_class(void);
 
 static inline void opstate_init(void)
 {