UBI: tweak volumes locking some more

Make the code more consistent by requiring the caller to lock the
ubi->volume_mutex, because this is what we do for updates.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

2 files changed, 17 insertions, 16 deletions

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 35d34b675c78..22c15a388f28 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -605,7 +605,9 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 
                 req.name[req.name_len] = '\0';
 
+                mutex_lock(&ubi->volumes_mutex);
                 err = ubi_create_volume(ubi, &req);
+                mutex_unlock(&ubi->volumes_mutex);
                 if (err)
                         break;
 
@@ -634,11 +636,14 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
                         break;
                 }
 
+                mutex_lock(&ubi->volumes_mutex);
                 err = ubi_remove_volume(desc);
+                mutex_unlock(&ubi->volumes_mutex);
+
                 /*
-                 * The volume is deleted, and the 'struct ubi_volume' object
-                 * will be freed when 'ubi_close_volume()' will call
-                 * 'put_device()'.
+                 * The volume is deleted (unless an error occurred), and the
+                 * 'struct ubi_volume' object will be freed when
+                 * 'ubi_close_volume()' will call 'put_device()'.
                  */
                 ubi_close_volume(desc);
                 break;
@@ -673,7 +678,9 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
                 pebs = !!do_div(tmp, desc->vol->usable_leb_size);
                 pebs += tmp;
 
+                mutex_lock(&ubi->volumes_mutex);
                 err = ubi_resize_volume(desc, pebs);
+                mutex_unlock(&ubi->volumes_mutex);
                 ubi_close_volume(desc);
                 break;
         }
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 18ef1e1da496..3ed63dc37386 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -189,7 +189,8 @@ static void volume_sysfs_close(struct ubi_volume *vol)
  * This function creates volume described by @req. If @req->vol_id id
  * %UBI_VOL_NUM_AUTO, this function automatically assign ID to the new volume
  * and saves it in @req->vol_id. Returns zero in case of success and a negative
- * error code in case of failure.
+ * error code in case of failure. Note, the caller has to have the
+ * @ubi->volumes_mutex locked.
  */
 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
 {
@@ -206,7 +207,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
         if (!vol)
                 return -ENOMEM;
 
-        mutex_lock(&ubi->volumes_mutex);
         spin_lock(&ubi->volumes_lock);
         if (vol_id == UBI_VOL_NUM_AUTO) {
                 /* Find unused volume ID */
@@ -356,7 +356,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
         spin_unlock(&ubi->volumes_lock);
 
         paranoid_check_volumes(ubi);
-        mutex_unlock(&ubi->volumes_mutex);
         return 0;
 
 out_sysfs:
@@ -383,7 +382,6 @@ out_acc:
         ubi->avail_pebs += vol->reserved_pebs;
 out_unlock:
         spin_unlock(&ubi->volumes_lock);
-        mutex_unlock(&ubi->volumes_mutex);
         if (dont_free)
                 put_device(&vol->dev);
         else
@@ -398,7 +396,8 @@ out_unlock:
  *
  * This function removes volume described by @desc. The volume has to be opened
  * in "exclusive" mode. Returns zero in case of success and a negative error
- * code in case of failure.
+ * code in case of failure. The caller has to have the @ubi->volumes_mutex
+ * locked.
  */
 int ubi_remove_volume(struct ubi_volume_desc *desc)
 {
@@ -413,7 +412,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc)
         if (ubi->ro_mode)
                 return -EROFS;
 
-        mutex_lock(&ubi->volumes_mutex);
         spin_lock(&ubi->volumes_lock);
         if (vol->ref_count > 1) {
                 /*
@@ -461,7 +459,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc)
         spin_unlock(&ubi->volumes_lock);
 
         paranoid_check_volumes(ubi);
-        mutex_unlock(&ubi->volumes_mutex);
         return 0;
 
 out_err:
@@ -470,7 +467,6 @@ out_err:
         ubi->volumes[vol_id] = vol;
 out_unlock:
         spin_unlock(&ubi->volumes_lock);
-        mutex_unlock(&ubi->volumes_mutex);
         return err;
 }
 
@@ -479,8 +475,9 @@ out_unlock:
  * @desc: volume descriptor
  * @reserved_pebs: new size in physical eraseblocks
  *
- * This function returns zero in case of success, and a negative error code in
- * case of failure.
+ * This function re-sizes the volume and returns zero in case of success, and a
+ * negative error code in case of failure. The caller has to have the
+ * @ubi->volumes_mutex locked.
  */
 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
 {
@@ -516,7 +513,6 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
         for (i = 0; i < reserved_pebs; i++)
                 new_mapping[i] = UBI_LEB_UNMAPPED;
 
-        mutex_lock(&ubi->volumes_mutex);
         spin_lock(&ubi->volumes_lock);
         if (vol->ref_count > 1) {
                 spin_unlock(&ubi->volumes_lock);
@@ -587,7 +583,6 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
         }
 
         paranoid_check_volumes(ubi);
-        mutex_unlock(&ubi->volumes_mutex);
         return 0;
 
 out_acc:
@@ -599,7 +594,6 @@ out_acc:
         }
 out_free:
         kfree(new_mapping);
-        mutex_unlock(&ubi->volumes_mutex);
         return err;
 }