[S390] cio: ccwgroup register vs. unregister.

Introduce a mutex for struct ccwgroup to prevent simuntaneous
register/unregister on the same ccwgroup device.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 18 insertions, 15 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 5aeb68e732b0..e5ccda63e883 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -75,8 +75,10 @@ static void ccwgroup_ungroup_callback(struct device *dev)
 {
         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 
+        mutex_lock(&gdev->reg_mutex);
         __ccwgroup_remove_symlinks(gdev);
         device_unregister(dev);
+        mutex_unlock(&gdev->reg_mutex);
 }
 
 static ssize_t
@@ -173,7 +175,8 @@ ccwgroup_create(struct device *root,
                 return -ENOMEM;
 
         atomic_set(&gdev->onoff, 0);
-
+        mutex_init(&gdev->reg_mutex);
+        mutex_lock(&gdev->reg_mutex);
         for (i = 0; i < argc; i++) {
                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 
@@ -183,12 +186,12 @@ ccwgroup_create(struct device *root,
                     || gdev->cdev[i]->id.driver_info !=
                     gdev->cdev[0]->id.driver_info) {
                         rc = -EINVAL;
-                        goto free_dev;
+                        goto error;
                 }
                 /* Don't allow a device to belong to more than one group. */
                 if (gdev->cdev[i]->dev.driver_data) {
                         rc = -EINVAL;
-                        goto free_dev;
+                        goto error;
                 }
                 gdev->cdev[i]->dev.driver_data = gdev;
         }
@@ -203,9 +206,8 @@ ccwgroup_create(struct device *root,
                         gdev->cdev[0]->dev.bus_id);
 
         rc = device_register(&gdev->dev);
-        
         if (rc)
-                goto free_dev;
+                goto error;
         get_device(&gdev->dev);
         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 
@@ -216,6 +218,7 @@ ccwgroup_create(struct device *root,
 
         rc = __ccwgroup_create_symlinks(gdev);
         if (!rc) {
+                mutex_unlock(&gdev->reg_mutex);
                 put_device(&gdev->dev);
                 return 0;
         }
@@ -224,19 +227,12 @@ ccwgroup_create(struct device *root,
 error:
         for (i = 0; i < argc; i++)
                 if (gdev->cdev[i]) {
-                        put_device(&gdev->cdev[i]->dev);
-                        gdev->cdev[i]->dev.driver_data = NULL;
-                }
-        put_device(&gdev->dev);
-        return rc;
-free_dev:
-        for (i = 0; i < argc; i++)
-                if (gdev->cdev[i]) {
                         if (gdev->cdev[i]->dev.driver_data == gdev)
                                 gdev->cdev[i]->dev.driver_data = NULL;
                         put_device(&gdev->cdev[i]->dev);
                 }
-        kfree(gdev);
+        mutex_unlock(&gdev->reg_mutex);
+        put_device(&gdev->dev);
         return rc;
 }
 
@@ -422,8 +418,12 @@ ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
         get_driver(&cdriver->driver);
         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
                                          __ccwgroup_match_all))) {
-                __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
+                struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+
+                mutex_lock(&gdev->reg_mutex);
+                __ccwgroup_remove_symlinks(gdev);
                 device_unregister(dev);
+                mutex_unlock(&gdev->reg_mutex);
                 put_device(dev);
         }
         put_driver(&cdriver->driver);
@@ -444,8 +444,10 @@ __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
         if (cdev->dev.driver_data) {
                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
                 if (get_device(&gdev->dev)) {
+                        mutex_lock(&gdev->reg_mutex);
                         if (device_is_registered(&gdev->dev))
                                 return gdev;
+                        mutex_unlock(&gdev->reg_mutex);
                         put_device(&gdev->dev);
                 }
                 return NULL;
@@ -465,6 +467,7 @@ ccwgroup_remove_ccwdev(struct ccw_device *cdev)
         if (gdev) {
                 __ccwgroup_remove_symlinks(gdev);
                 device_unregister(&gdev->dev);
+                mutex_unlock(&gdev->reg_mutex);
                 put_device(&gdev->dev);
         }
 }