UBI: add UBI devices reference counting

This is one more step on the way to "removable" UBI devices. It
adds reference counting for UBI devices. Every time a volume on
this device is opened - the device's refcount is increased. It
is also increased if someone is reading any sysfs file of this
UBI device or of one of its volumes.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index c94f475758de..85297cde4ac5 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -339,6 +339,7 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
 {
         int err, pnum, vol_id = vol->vol_id;
 
+        ubi_assert(ubi->ref_count > 0);
         ubi_assert(vol->ref_count > 0);
 
         if (ubi->ro_mode)
@@ -389,6 +390,7 @@ int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
         struct ubi_vid_hdr *vid_hdr;
         uint32_t uninitialized_var(crc);
 
+        ubi_assert(ubi->ref_count > 0);
         ubi_assert(vol->ref_count > 0);
 
         err = leb_read_lock(ubi, vol_id, lnum);
@@ -614,6 +616,7 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
         int err, pnum, tries = 0, vol_id = vol->vol_id;
         struct ubi_vid_hdr *vid_hdr;
 
+        ubi_assert(ubi->ref_count > 0);
         ubi_assert(vol->ref_count > 0);
 
         if (ubi->ro_mode)
@@ -749,6 +752,7 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
         struct ubi_vid_hdr *vid_hdr;
         uint32_t crc;
 
+        ubi_assert(ubi->ref_count > 0);
         ubi_assert(vol->ref_count > 0);
 
         if (ubi->ro_mode)
@@ -865,6 +869,7 @@ int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
         struct ubi_vid_hdr *vid_hdr;
         uint32_t crc;
 
+        ubi_assert(ubi->ref_count > 0);
         ubi_assert(vol->ref_count > 0);
 
         if (ubi->ro_mode)