[PATCH] mtd/ubi: fix initialization order of ubi subsystems

[Mikhail Kshevetskiy <mikhail.kshevetskiy@xxxxxxxxx>]

during ubi initialization we have a following calling sequence

1) ubi_attach()

   ----------------------------------------------------------------
   err = ubi_wl_init(ubi, ai);
   if (err) goto out_vtbl;

   err = ubi_eba_init(ubi, ai);
   if (err) goto out_wl;
   ----------------------------------------------------------------

   As we can see "eba" subsytem is NOT initialized at the moment of
   initializing of "wl" subsystem

2) ubi_wl_init()

   it call ensure_wear_leveling() at some moment

3) ensure_wear_leveling()

   ---------------------------------------------------------------
   e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
   e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
   if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) goto out_unlock;
   dbg_wl("schedule wear-leveling");
   ---------------------------------------------------------------

   so, if no wear-leveling is scheduled than everything is OK

   and a little bit below

   ---------------------------------------------------------------
   wrk->anchor = 0;
   wrk->func = &wear_leveling_worker;
   if (nested) __schedule_ubi_work(ubi, wrk);
   else schedule_ubi_work(ubi, wrk);
   ---------------------------------------------------------------

   as result we enter to wear_leveling_worker() function

4) wear_leveling_worker()

   ---------------------------------------------------------------
   /*
    * Now pick the least worn-out used physical eraseblock and a
    * highly worn-out free physical eraseblock. If the erase
    * counters differ much enough, start wear-leveling.
    */
   e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
   e2 = get_peb_for_wl(ubi);
   if (!e2) goto out_cancel;

   if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
       dbg_wl("no WL needed: min used EC %d, max free EC %d", e1->ec, e2->ec);
       /* Give the unused PEB back */
       wl_tree_add(e2, &ubi->free);
       ubi->free_count++;
       goto out_cancel;
   }
   ---------------------------------------------------------------

   so, if no WL needed than everything is OK

   and a little bit below

   ---------------------------------------------------------------
   err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
   ---------------------------------------------------------------

   OPS, eba sybsystem is not initialized yet (see (1))

>From the other side, it looks like eba sybsystem does not require wl sybsystem
during initialization, so just fix ordering and proper handle error path.
---
 drivers/mtd/ubi/attach.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index 10b2459f8951..8c1d629c0e1d 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -1602,13 +1602,13 @@ int ubi_attach(struct ubi_device *ubi, int force_scan)
 	if (err)
 		goto out_ai;
 
-	err = ubi_wl_init(ubi, ai);
+	err = ubi_eba_init(ubi, ai);
 	if (err)
 		goto out_vtbl;
 
-	err = ubi_eba_init(ubi, ai);
+	err = ubi_wl_init(ubi, ai);
 	if (err)
-		goto out_wl;
+		goto out_vtbl;
 
 #ifdef CONFIG_MTD_UBI_FASTMAP
 	if (ubi->fm && ubi_dbg_chk_fastmap(ubi)) {
-- 
2.20.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/