s390/dasd: Fix inconsistent kobject removal

Our intention was to only remove path kobjects whenever a device is
being set offline. However, one corner case was missing.

If a device is disabled and enabled (using the IOCTLs BIODASDDISABLE and
BIODASDENABLE respectively), the enabling process will call
dasd_eckd_reload_device() which itself calls dasd_eckd_read_conf() in
order to update path information. During that update,
dasd_eckd_clear_conf_data() clears all old data and also removes all
kobjects. This will leave us with an inconsistent state of path kobjects
and a subsequent path verification leads to a failing kobject creation.

Fix this by removing kobjects only in the context of offlining a device
as initially intended.

Fixes: 19508b204740 ("s390/dasd: Display FC Endpoint Security information via sysfs")
Reported-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 14 insertions, 6 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 16bb135c20aa52..03d27ee9cac65e 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -1874,18 +1874,26 @@ void dasd_path_create_kobjects(struct dasd_device *device)
 }
 EXPORT_SYMBOL(dasd_path_create_kobjects);
 
-/*
- * As we keep kobjects for the lifetime of a device, this function must not be
- * called anywhere but in the context of offlining a device.
- */
-void dasd_path_remove_kobj(struct dasd_device *device, int chp)
+static void dasd_path_remove_kobj(struct dasd_device *device, int chp)
 {
 	if (device->path[chp].in_sysfs) {
 		kobject_put(&device->path[chp].kobj);
 		device->path[chp].in_sysfs = false;
 	}
 }
-EXPORT_SYMBOL(dasd_path_remove_kobj);
+
+/*
+ * As we keep kobjects for the lifetime of a device, this function must not be
+ * called anywhere but in the context of offlining a device.
+ */
+void dasd_path_remove_kobjects(struct dasd_device *device)
+{
+	int i;
+
+	for (i = 0; i < 8; i++)
+		dasd_path_remove_kobj(device, i);
+}
+EXPORT_SYMBOL(dasd_path_remove_kobjects);
 
 int dasd_add_sysfs_files(struct ccw_device *cdev)
 {