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

[Richard Weinberger <richard.weinberger@xxxxxxxxx>]

On Thu, Jun 20, 2019 at 3:28 PM Mikhail Kshevetskiy
<mikhail.kshevetskiy@xxxxxxxxx> wrote:
>
> 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

Well, we schedule work, but don't execute it since the ubi-thread
is still disabled.

Can you please share a little more about the problem you are facing?
Also produce_free_peb() should not get called at this point.
So before we flip the order of initialization I'd like to understand the problem
better.

Thanks,
//richard

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