[S390] cio: ccwgroup register vs. unregister.
Cornelia Huck [Fri, 27 Apr 2007 14:01:37 +0000 (16:01 +0200)]
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>

drivers/s390/cio/ccwgroup.c
include/asm-s390/ccwgroup.h

index 5aeb68e..e5ccda6 100644 (file)
@@ -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);
        }
 }
index d2f9c0d..925b3dd 100644 (file)
@@ -11,6 +11,7 @@ struct ccwgroup_device {
                CCWGROUP_ONLINE,
        } state;
        atomic_t onoff;
+       struct mutex reg_mutex;
        unsigned int count;             /* number of attached slave devices */
        struct device   dev;            /* master device                    */
        struct ccw_device *cdev[0];     /* variable number, allocate as needed */