Introduce a new list to the UBI attach information
object to be able to deal better with old and corrupted
Fastmap eraseblocks.
Also move more Fastmap specific code into fastmap.c.
Signed-off-by: NRichard Weinberger <richard@nod.at>

Set free_count to zero before walking through ai->erase list
in wl_init().

Found in U-Boot as U-Boot has no workqueue/threads, it immediately
calls erase_worker(), which increase for each erased block
free_count. Without this patch, free_count gets after
this initialized to zero in wl_init(), so the free_count
variable always has the maybe wrong value 0 in U-Boot.
Signed-off-by: NHeiko Schocher <hs@denx.de>
Reviewed-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>

wear_leveling_worker() currently unconditionally puts a PEB on erase in
the error case even it just been taken from the free_list and never
used.
In case the PEB was never used it can be put back on the free list
saving a precious erase cycle.

v1…v2:
	- to_leb_clean -> dst_leb_clean
	- use the nested option for ensure_wear_leveling()
	- do_sync_erase() can't go -ENOMEM so we can just go into
	  RO-mode now.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NRichard Weinberger <richard@nod.at>

If __erase_worker() fails to erase the EB and schedule_erase() fails as
well to do anything about it then we go RO. But that is not a reason to
leak the e argument here. Therefore clean up e.

Cc: <stable@vger.kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NRichard Weinberger <richard@nod.at>

Since fastmap we gained do_sync_erase(). This function can return an error
and its error handling isn't obvious. First the memory allocation for
struct ubi_work can fail and as such struct ubi_wl_entry is leaked.
However if the memory allocation succeeds then the tail function takes
care of the struct ubi_wl_entry. A free here could result in a double
free.
To make the error handling simpler, I split the tail function into one
piece which does the work and another which frees the struct ubi_work
which is passed as argument. As result do_sync_erase() can keep the
struct on stack and we get rid of one error source.

Cc: <stable@vger.kernel.org>
Fixes: 8199b901 ("UBI: Add fastmap support to the WL sub-system")
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NRichard Weinberger <richard@nod.at>

UBI: attaching mtd1 to ubi0
UBI: scanning is finished
UBI error: init_volumes: not enough PEBs, required 706, available 686
UBI error: ubi_wl_init: no enough physical eraseblocks (-20, need 1)
UBI error: ubi_attach_mtd_dev: failed to attach mtd1, error -12 <= NOT ENOMEM
UBI error: ubi_init: cannot attach mtd1

If available PEBs are not enough when initializing volumes, return -ENOSPC
directly. If available PEBs are not enough when initializing WL, return
-ENOSPC instead of -ENOMEM.

Cc: stable@vger.kernel.org
Signed-off-by: NSheng Yong <shengyong1@huawei.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NDavid Gstir <david@sigma-star.at>

Signed-off-by: NSheng Yong <shengyong1@huawei.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>

This function was added to fastmap in a very early stage
to have paranoid assertions.
With the current fastmap implementation this assert will never
trigger as fastmap PEBs are not seen by the WL sub-system.
Remove it to save us some CPU cycles.
Signed-off-by: NRichard Weinberger <richard@nod.at>

...and kill another #ifdef.
Signed-off-by: NRichard Weinberger <richard@nod.at>

...and kill another #ifdef in wl.c. :-)
Signed-off-by: NRichard Weinberger <richard@nod.at>

Fastmap is tightly connected to the WL sub-system, many fastmap-specific
functionslive in wl.c.
To get rid of most #ifdefs in wl.c move this functions into a new file
and include it into wl.c
Signed-off-by: NRichard Weinberger <richard@nod.at>

In some error paths the WL sub-system gives up on a PEB
and frees it's ubi_wl_entry struct but does not set
the entry in ubi->lookuptbl to NULL.
Fastmap can stumble over such a stale pointer as it uses
ubi->lookuptbl to find all PEBs.

Fix this by introducing a new helper function which free()s
a WL entry and removes the reference from the lookup table.
Signed-off-by: NRichard Weinberger <richard@nod.at>

a) Rename ubi->fm_sem to ubi->fm_eba_sem as this semaphore
protects EBA changes.
b) Turn ubi->fm_mutex into a rw semaphore. It will still serialize
fastmap writes but also ensures that ubi_wl_put_peb() is not
interrupted by a fastmap write. We use a rw semaphore to allow
ubi_wl_put_peb() still to be executed in parallel if no fastmap
write is happening.
Signed-off-by: NRichard Weinberger <richard@nod.at>

ubi_wl_get_peb() returns a fresh PEB which can be used by
user of UBI. Due to the pool logic fastmap will correctly
map this PEB upon attach time because it will be scanned.

If a new fastmap is written (due to heavy parallel io)
while the before the fresh PEB is assigned to the EBA table
it will not be scanned as it is no longer in the pool.
So, the race window exists between ubi_wl_get_peb()
and the EBA table assignment.
We have to make sure that no new fastmap can be written
while that.

To ensure that ubi_wl_get_peb() will grab ubi->fm_sem in read mode
and the user of ubi_wl_get_peb() has to release it after the PEB
got assigned.
Signed-off-by: NRichard Weinberger <richard@nod.at>

If ubi_update_fastmap() fails notify the user.
This is not a hard error as ubi_update_fastmap() makes sure that upon failure
the current on-flash fastmap will no be used upon next UBI attach.
Signed-off-by: NRichard Weinberger <richard@nod.at>

Add a ubi_fastmap_close() to free all resources used by fastmap
at WL shutdown.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Tested-by: NGuido Martínez <guido@vanguardiasur.com.ar>
Reviewed-by: NGuido Martínez <guido@vanguardiasur.com.ar>

There is no need to allocate new ones every time, we can reuse
the existing ones.
This makes the code cleaner and more easy to follow.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NTanya Brokhman <tlinder@codeaurora.org>
Reviewed-by: NGuido Martínez <guido@vanguardiasur.com.ar>

Currently ubi_refill_pools() first fills the first and then
the second one.
If only very few free PEBs are available the second pool can get
zero PEBs.
Change ubi_refill_pools() to distribute free PEBs fair between
all pools.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NGuido Martínez <guido@vanguardiasur.com.ar>

Make it two functions, wl_get_wle() and wl_get_peb().
wl_get_peb() works exactly like __wl_get_peb() but wl_get_wle()
does not call produce_free_peb().
While refilling the fastmap user pool we cannot release ubi->wl_lock
as produce_free_peb() does.
Hence the fastmap logic uses now wl_get_wle().
Signed-off-by: NRichard Weinberger <richard@nod.at>

ubi_wl_get_peb() has two problems, it reads the pool
size and usage counters without any protection.
While reading one value would be perfectly fine it reads multiple
values and compares them. This is racy and can lead to incorrect
pool handling.
Furthermore ubi_update_fastmap() is called without wl_lock held,
before incrementing the used counter it needs to be checked again.
It could happen that another thread consumed all PEBs from the
pool and the counter goes beyond ->size.
Signed-off-by: NRichard Weinberger <richard@nod.at>

...otherwise the deferred work might run after datastructures
got freed and corrupt memory.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NGuido Martínez <guido@vanguardiasur.com.ar>

If the WL pool runs out of PEBs we schedule a fastmap write
to refill it as soon as possible.
Ensure that only one at a time is scheduled otherwise we might end in
a fastmap write storm because writing the fastmap can schedule another
write if bitflips are detected.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NTanya Brokhman <tlinder@codeaurora.org>
Reviewed-by: NGuido Martínez <guido@vanguardiasur.com.ar>

In some of the 'out_not_moved' error paths, lnum may be used
uninitialized. Don't ignore the warning; let's fix it.

This uninitialized variable doesn't have much visible effect in the end,
since we just schedule the PEB for erasure, and its LEB number doesn't
really matter (it just gets printed in debug messages). But let's get it
straight anyway.

Coverity CID #113449

Cc: stable <stable@vger.kernel.org>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>

Some cosmetic fixes to the patch "UBI: Extend UBI layer debug/messaging
capabilities".
Signed-off-by: NTanya Brokhman <tlinder@codeaurora.org>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

If the erase worker is unable to erase a PEB it will
free the ubi_wl_entry itself.
The failing ubi_wl_entry must not free()'d again after
do_sync_erase() returns.

Cc: <stable@vger.kernel.org>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

If there is more then one UBI device mounted, there is no way to
distinguish between messages from different UBI devices.
Add device number to all ubi layer message types.

The R/O block driver messages were replaced by pr_* since
ubi_device structure is not used by it.

Amended a bit by Artem.
Signed-off-by: NTanya Brokhman <tlinder@codeaurora.org>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

s/of/if/
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

It confused me more than once that the cancel flag of the
work function does not indicate the cancellation of a single work.
In fact it indicates the WL sub-system shutdown and therefore
worker functions have to free their wl_entries too.
That's why you cannot cancel a single work, you can only shutdown
all works.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

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

Use the _safe variant because we're iterating over a list where items get
deleted and freed.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

The ubi->free_count should be updated with every insert/remove to/from
the ubi->free list.
Signed-off-by: NTanya Brokhman <tlinder@codeaurora.org>
Reviewed-by: NDolev Raviv <draviv@codeaurora.org>
Acked-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

In case of an error (if there are not free PEB's for example),
__wl_get_peb will return a negative value. In order to prevent access
violation we need to test the returned value prior to using it later on.
Signed-off-by: NTatyana Brokhman <tlinder@codeaurora.org>
Reviewed-by: NDolev Raviv <draviv@codeaurora.org>
Acked-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

If no free PEBs are available refill_wl_user_pool() must not
return with -ENOSPC immediately.
It has to block till produce_free_peb() produced a free PEB.
Reported-and-Tested-by: NRichard Genoud <richard.genoud@gmail.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

get_peb_for_wl() removes the PEB from the free list.
If the WL subsystem detects that no wear leveling is needed
it cancels the operation and drops the gained PEB.
In this case we have to put the PEB back into the free list.

This issue was introduced with commit ed4b7021
(UBI: remove PEB from free tree in get_peb_for_wl()).

Cc: <stable@vger.kernel.org> # 3.7.x
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

With this patch code is a bit more readable and there's no
generated code or functionality impact.
Furthermore, this abstracts implementation details and
will allow to change ubi_debug_info in a less invasive way.
Signed-off-by: NEzequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

As ubi_self_check_all_ff() might sleep we are not allowed
to call it from atomic context.
For now we call it only from ubi_wl_get_peb().
There are some code paths where it would also make sense,
but these paths are currently atomic and only enabled
when fastmap is used.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

If UBI is built without fastmap, get_peb_for_wl() has to
remove the PEB manially from the free tree.
Otherwise the requested PEB lives in two trees.
Reported-by: NZach Sadecki <zsadecki@itwatchdogs.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

This line of comment looks completely bogus.

It was introduced in:
commit d99383b0
Author: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Date:   Wed May 18 14:47:34 2011 +0300

    UBI: change the interface of a debugging check function

Remove it.
Signed-off-by: NEzequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

To make fastmap possible the WL sub-system needs some
changes.
Mostly to support fastmaps pools.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

This patch adds fastmap specific data structures to ubi.h.
It moves also struct ubi_work to ubi.h as it is now needed
for more than one c file.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>