UBI: use separate mutex for volumes checking

Introduce a separate mutex which serializes volumes checking,
because we cammot really use volumes_mutex - it cases reverse
locking problems with mtd_tbl_mutex when gluebi is used -
thanks to lockdep.

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

3 files changed, 5 insertions, 8 deletions

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 70c0b9a9e6e3..6ac133994f94 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -703,6 +703,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
                 goto out_free;
 
         mutex_init(&ubi->buf_mutex);
+        mutex_init(&ubi->ckvol_mutex);
         ubi->peb_buf1 = vmalloc(ubi->peb_size);
         if (!ubi->peb_buf1)
                 goto out_free;
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 4ec3a33b2577..146957c3380d 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -169,17 +169,12 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
         desc->vol = vol;
         desc->mode = mode;
 
-        /*
-         * To prevent simultaneous checks of the same volume we use
-         * @volumes_mutex, although it is not the purpose it was introduced
-         * for.
-         */
-        mutex_lock(&ubi->volumes_mutex);
+        mutex_lock(&ubi->ckvol_mutex);
         if (!vol->checked) {
                 /* This is the first open - check the volume */
                 err = ubi_check_volume(ubi, vol_id);
                 if (err < 0) {
-                        mutex_unlock(&ubi->volumes_mutex);
+                        mutex_unlock(&ubi->ckvol_mutex);
                         ubi_close_volume(desc);
                         return ERR_PTR(err);
                 }
@@ -190,7 +185,7 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
                 }
                 vol->checked = 1;
         }
-        mutex_unlock(&ubi->volumes_mutex);
+        mutex_unlock(&ubi->ckvol_mutex);
 
         return desc;
 
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 2a6171226f1f..ef22f922f580 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -392,6 +392,7 @@ struct ubi_device {
         void *peb_buf1;
         void *peb_buf2;
         struct mutex buf_mutex;
+        struct mutex ckvol_mutex;
 #ifdef CONFIG_MTD_UBI_DEBUG
         void *dbg_peb_buf;
         struct mutex dbg_buf_mutex;