ubi: Fix race condition between ubi volume creation and udev

BugLink: http://bugs.launchpad.net/bugs/1751064
commit a51a0c8d213594bc094cb8e54aad0cb6d7f7b9a6 upstream.

Similar to commit 714fb87e8bc0 ("ubi: Fix race condition between ubi
device creation and udev"), we should make the volume active before
registering it.

Signed-off-by: Clay McClure <clay@daemons.net>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 85237cf661f9242bc02b0432bb0c2e5e5109672e..3fd8d7ff7a02ff7bc63a36418ab6734a9f0650de 100644 (file)
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -270,6 +270,12 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
                        vol->last_eb_bytes = vol->usable_leb_size;
        }
 
+       /* Make volume "available" before it becomes accessible via sysfs */
+       spin_lock(&ubi->volumes_lock);
+       ubi->volumes[vol_id] = vol;
+       ubi->vol_count += 1;
+       spin_unlock(&ubi->volumes_lock);
+
        /* Register character device for the volume */
        cdev_init(&vol->cdev, &ubi_vol_cdev_operations);
        vol->cdev.owner = THIS_MODULE;
@@ -298,11 +304,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
        if (err)
                goto out_sysfs;
 
-       spin_lock(&ubi->volumes_lock);
-       ubi->volumes[vol_id] = vol;
-       ubi->vol_count += 1;
-       spin_unlock(&ubi->volumes_lock);
-
        ubi_volume_notify(ubi, vol, UBI_VOLUME_ADDED);
        self_check_volumes(ubi);
        return err;
@@ -315,6 +316,10 @@ out_sysfs:
         */
        cdev_device_del(&vol->cdev, &vol->dev);
 out_mapping:
+       spin_lock(&ubi->volumes_lock);
+       ubi->volumes[vol_id] = NULL;
+       ubi->vol_count -= 1;
+       spin_unlock(&ubi->volumes_lock);
        ubi_eba_destroy_table(eba_tbl);
 out_acc:
        spin_lock(&ubi->volumes_lock);