UBI: Fix livelock in produce_free_peb()

The while loop in produce_free_peb() assumes that each work will produce a
free PEB. This is not true.
If ubi->works_count is 1 and the only scheduled work is the
wear_leveling_worker() produce_free_peb() can loop forever in case
nobody schedules an erase work.
Fix this issue by checking in the while loop whether work is scheduled.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 20f4917131450f844332183756a25bce6f28d9a9..32b3c1486a05960a66f542d8ab3ecc24b6a9cf66 100644 (file)
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -272,7 +272,7 @@ static int produce_free_peb(struct ubi_device *ubi)
 {
        int err;
 
 {
        int err;
 

-       while (!ubi->free.rb_node) {
+       while (!ubi->free.rb_node && ubi->works_count) {

                spin_unlock(&ubi->wl_lock);
 
                dbg_wl("do one work synchronously");
                spin_unlock(&ubi->wl_lock);
 
                dbg_wl("do one work synchronously");