ubi: Add six fault injection type for testing

This commit adds six fault injection type for testing to cover the
abnormal path of the UBI driver.

Inject the following faults when the UBI reads the LEB:
+----------------------------+-----------------------------------+
| Interface name | emulate behavior |
+----------------------------+-----------------------------------+
| emulate_eccerr | ECC error |
+----------------------------+-----------------------------------+
| emulate_read_failure | read failure |
|----------------------------+-----------------------------------+
| emulate_io_ff | read content as all FF |
|----------------------------+-----------------------------------+
| emulate_io_ff_bitflips | content FF with MTD err reported |
+----------------------------+-----------------------------------+
| emulate_bad_hdr | bad leb header |
|----------------------------+-----------------------------------+
| emulate_bad_hdr_ebadmsg | bad header with ECC err |
+----------------------------+-----------------------------------+

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: Use the fault injection framework to enhance the fault injection capability

To make debug parameters configurable at run time, use the
fault injection framework to reconstruct the debugfs interface,
and retain the legacy fault injection interface.

Now, the file emulate_failures and fault_attr files control whether
to enable fault emmulation.

The file emulate_failures receives a mask that controls type and
process of fault injection. Generally, for ease of use, you can
directly enter a mask with all 1s.

echo 0xffff > /sys/kernel/debug/ubi/ubi0/emulate_failures

And you need to configure other fault-injection capabilities for
testing purpose:

echo 100 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/probability
echo 15 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/space
echo 2 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/verbose
echo -1 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/times

The CONFIG_MTD_UBI_FAULT_INJECTION to enable the Fault Injection is
added to kconfig.

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: Fix repeated words in comments

Delete the redundant word 'a'.
Delete the redundant word 'the'.

Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: remove dead code in validate_vid_hdr()

data_size is already checked against zero when vol_type matches
UBI_VID_STATIC. Remove the following dead code.

Signed-off-by: Jubin Zhong <zhongjubin@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: Do not zero out EC and VID on ECC-ed NOR flashes

For NOR flashes EC and VID are zeroed out before an erase is issued to
make sure UBI does not mistakenly treat the PEB as used and associate it
with an LEB.

But on some flashes, like the Cypress Semper S28 SPI NOR flash family,
multi-pass page programming is not allowed on the default ECC scheme.
This means zeroing out these magic numbers will result in the flash
throwing a page programming error.

Do not zero out EC and VID for such flashes. A writesize > 1 is an
indication of an ECC-ed flash.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

mm: remove the pgprot argument to __vmalloc

The pgprot argument to __vmalloc is always PAGE_KERNEL now, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com> [hyperv]
Acked-by: Gao Xiang <xiang@kernel.org> [erofs]
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-22-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mtd: Unconditionally update ->fail_addr and ->addr in part_erase()

->fail_addr and ->addr can be updated no matter the result of
parent->_erase(), we just need to remove the code doing the same thing
in mtd_erase_callback() to avoid adjusting those fields twice.

Note that this can be done because all MTD users have been converted to
not pass an erase_info->callback() and are thus only taking the
->addr_fail and ->addr fields into account after part_erase() has
returned.

While we're at it, get rid of the erase_info->mtd field which was only
needed to let mtd_erase_callback() get the partition device back.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>

mtd: Stop assuming mtd_erase() is asynchronous

None of the mtd->_erase() implementations work in an asynchronous manner,
so let's simplify MTD users that call mtd_erase(). All they need to do
is check the value returned by mtd_erase() and assume that != 0 means
failure.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>

UBI: Fix typos

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

UBI: introduce the VID buffer concept

Currently, all VID headers are allocated and freed using the
ubi_zalloc_vid_hdr() and ubi_free_vid_hdr() function. These functions
make sure to align allocation on ubi->vid_hdr_alsize and adjust the
vid_hdr pointer to match the ubi->vid_hdr_shift requirements.
This works fine, but is a bit convoluted.
Moreover, the future introduction of LEB consolidation (needed to support
MLC/TLC NANDs) will allows a VID buffer to contain more than one VID
header.

Hence the creation of a ubi_vid_io_buf struct to attach extra information
to the VID header.

We currently only store the actual pointer of the underlying buffer, but
will soon add the number of VID headers contained in the buffer.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: Only read necessary size when reading the VID header

When reading the vid hdr from the device UBI always reads a whole
page. Instead, read only the data we actually need and speed up
attachment of UBI devices by potentially making use of reading
subpages if the NAND driver supports it.

Since the VID header may be at offset vid_hdr_shift in the page and
we can only read from the beginning of a page we have to add that
offset to the read size.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

UBI: fix use of "VID" vs. "EC" in header self-check

Looks like a typo, using UBI_EC_HDR_SIZE_CRC (note the "EC") to compute
the CRC for the VID header.

This shouldn't cause any functional change, as both structures are 64
bytes. Verified with:

BUILD_BUG_ON(UBI_VID_HDR_SIZE_CRC != UBI_EC_HDR_SIZE_CRC);

Reported here:
http://lists.infradead.org/pipermail/linux-mtd/2013-September/048570.html

Reported by: Bill Pringlemeir <bpringlemeir@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

UBI: Validate data_size

Make sure that data_size is less than LEB size.
Otherwise a handcrafted UBI image is able to trigger
an out of bounds memory access in ubi_compare_lebs().

Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: David Gstir <david@sigma-star.at>

UBI: power cut emulation for testing

Emulate random power cuts by switching device to ro after a number of
writes to allow simple power cut testing with nand-sim.

Maximum and minimum number of successful writes before power cut and
what kind of writes (EC header, VID header or none) to interrupt
configurable via debugfs.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>

UBI: extend UBI layer debug/messaging capabilities - cosmetics

Some cosmetic fixes to the patch "UBI: Extend UBI layer debug/messaging
capabilities".

Signed-off-by: Tanya Brokhman <tlinder@codeaurora.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: Extend UBI layer debug/messaging capabilities

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: Tanya Brokhman <tlinder@codeaurora.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: avoid program operation on NOR flash after erasure interrupted

nor_erase_prepare() will be called before erase a NOR flash, it will program '0'
into a block to mark this block. But program data into a erasure interrupted block
can cause program timtout(several minutes at most) error, could impact other
operation on NOR flash. So UBIFS can read this block first to avoid unneeded
program operation.

This patch try to put read operation at head of write operation in
nor_erase_prepare(), read out the data.
If the data is already corrupt, then no need to program any data into this block,
just go to erase this block.

This patch is validated on Micron NOR flash, part number is：JS28F512M29EWHA

Signed-off-by: Qi Wang <qiwang@micron.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: introduce helpers dbg_chk_{io, gen}

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: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: print less

UBI currently prints a lot of information when it mounts a volume, which
bothers some people. Make it less chatty - print only important information
by default.

Get rid of 'dbg_msg()' macro completely.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: comply with coding style

Join all the split printk lines in order to stop checkpatch complaining.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: amend comments after all the renamings

This patch amends commentaries in scan.[ch] to match the new logic. Reminder -
we did the restructuring to prepare the code for adding the fastmap. This patch
also renames a couple of functions - it was too difficult to separate out that
change and I decided that it is not too bad to have it in the same patch with
commentaries changes.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: rename few functions for consistency

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: get rid of dbg_err

This patch removes the 'dbg_err()' macro and we now use 'ubi_err' instead.
The idea of 'dbg_err()' was to compile out some error message to make the
binary a bit smaller - but I think it was a bad idea.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: clean-up terminology for self-checks in io.c

We have the "sefl-check" feature in UBI, but for historical reasons many
corresponding functions and commentaries in the code use term "paranoid check"
instead. Let's clean this up and use "self-check" everywhere.

This patch renames functions, amends comments and messages. It touches only the
io.c file.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: remove Kconfig debugging option

This patch kills the UBI debugging Kconfig option completely and makes all the
debugging stuff to be always compiled-in. It was pain in the neck to maintain
this useless option because all users I am aware of have debugging enabled
anyway - how else will you diagnose errors otherwise?

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: always warn if case of I/O errors

Currently UBI silently retries I/O operation in case of errors. This patch
makes it emit a warning before retrying. This should allow users notice issues
earlier.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: always dump VID and EC headers in case of errors

UBI (and UBIFS) are a bit over-engineered WRT debugging. The idea was to
link as few as possible when debugging is disabled, but the downside is
that most people produce bug reports which are difficult to understand.

Always dump the VID and EC headers' contents in case of errors when it
is helpful.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: always dump flash contents in case of errors

UBI (and UBIFS) are a bit over-engineered WRT debugging. The idea was to
link as few as possible when debugging is disabled, but the downside is
that most people produce bug reports which are difficult to understand.

Always dump the flash contents in case of errors, not only when debugging is
enabled.

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

UBI: always dump the stack on error

UBI (and UBIFS) are a bit over-engineered WRT debugging. The idea was to
link as few as possible when debugging is disabled, but the downside is
that most people produce bug reports which are difficult to understand.

This patch weeds out the 'ubi_dbg_dump_stack()' function and turns it
into 'dump_stack()' - it is always useful to have stack dump in case of
an error.

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

UBI: rename peb_buf1 to peb_buf

Now we have only one buffer so let's rename it to just 'peb_buf1'.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

mtd: introduce mtd_block_markbad interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_block_isbad interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_write interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_read interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_erase interface

This patch is part of a patch-set which changes the MTD interface
from 'mtd->func()' form to 'mtd_func()' form. We need this because
we want to add common code to to all drivers in the mtd core level,
which is impossible with the current interface when MTD clients
call driver functions like 'read()' or 'write()' directly.

At this point we just introduce a new inline wrapper function, but
later some of them are expected to gain more code. E.g., the input
parameters check should be moved to the wrappers rather than be
duplicated at many drivers.

This particular patch introduced the 'mtd_erase()' interface. The
following patches add all the other interfaces one by one.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: utilize `mtd_is_*()' functions

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

UBI: prepare debugging stuff to further debugfs conversion

We'll need the 'struct ubi_device *ubi' pointer in every debugging function (to
access the ->dbg field), so add this pointer to all the functions implementing
UBI debugging test modes like 'ubi_dbg_is_bitflip()' etc.

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

UBI: use debugfs for the extra checks knobs

This patch introduces debugfs support to UBI. All the UBI stuff is kept in the
"ubi" debugfs directory, which contains per-UBI device "ubi/ubiX"
sub-directories, containing debugging files. This file also creates
"ubi/ubiX/chk_gen" and "ubi/ubiX/chk_io" knobs for switching general and I/O
extra checks on and off. And it removes the 'debug_chks' UBI module parameters.

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

UBI: fix typo in a message

When a PEB passes the torture test, UBI prints
"do not mark it a bad", but should print "do not mark it as bad".
This patch corrects the typo.

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

UBI: fix minor stylistic issues

Fix checkpatch.pl errors and warnings:

* space before tab
* line over 80 characters
* include linux/ioctl.h instead of asm/ioctl.h

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

UBI: check if we are in RO mode in the erase routine

'do_sync_erase()' has to check whether we are in R/O mode before
erasing the PEB. This patch adds the check and while on it, adds an
assertion which validates the 'pnum' argument, as well as removes
a check which is always true because it has already been done
few lines before.

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

UBI: use GFP_NOFS properly

This patch fixes a brown-paperbag bug which was introduced by me:
I used incorrect "GFP_KERNEL | GFP_NOFS" allocation flags to make
sure my allocations do not cause write-back. But the correct form
is "GFP_NOFS".

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

UBI: make self-checks dynamic

This patch adds a possibility to dynamically switch UBI self-checks
on and off, instead of toggling them compile-time from the configuration
menu. This is much more flexible, and consistent with UBIFS, and this
also simplifies UBI Kconfig menu and the code.

This patch introduces two levels of self-checks - general, which
includes all self-checks which are relatively fast, and I/O, which
includes write-verify checks and erase-verify checks, which are
relatively slow and involve flash I/O.

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

UBI: remove UBI_IO_DEBUG macro

This additional little macro is used to print a bit more messages
while scanning the media. However, we have the 'dbg_bld()' macro
for this, so we better us 'dbg_bld()' and kill UBI_IO_DEBUG. This
simplifies the code a tiny bit.

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

UBI: allocate erase checking buffer on demand

Instead of using pre-allocated 'ubi->dbg_peb_buf' buffer in
'ubi_dbg_check_all_ff()', dynamically allocate it when needed. The
intend is to get rid of the pre-allocated 'ubi->dbg_peb_buf' buffer
completely. And the need for this arises because we want to change
to dynamic debugging control instead of compile-time control, i.e.,
we are going to kill the CONFIG_MTD_UBI_DEBUG_PARANOID Kconfig
option, which would mean that 'ubi->dbg_peb_buf' is always allocated,
which would be wasteful.

Thus, we are getting rid of 'ubi->dbg_peb_buf', and this is a
preparation for that.

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

UBI: allocate write checking buffer on demand

Instead of using pre-allocated 'ubi->dbg_peb_buf' buffer in
'ubi_dbg_check_write()', dynamically allocate it when needed. The
intend is to get rid of the pre-allocated 'ubi->dbg_peb_buf' buffer
completely. And the need for this arises because we want to change
to dynamic debugging control instead of compile-time control, i.e.,
we are going to kill the CONFIG_MTD_UBI_DEBUG_PARANOID Kconfig
option, which would mean that 'ubi->dbg_peb_buf' is always allocated,
which would be wasteful.

Thus, we are getting rid of 'ubi->dbg_peb_buf', and this is a
preparation for that.

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

UBI: always re-read in case of read failures

When the read operation fails, UBI tries to re-read several times in
a hope that one of the subsequent reads may succeed. However, currently
UBI re-reads only if MTD failed to read all data, but does not re-reads
if all the data were read, but with an integrity error (-EBADMSB). This
patch makes UBI to always re-try reading.

This should be useful for reading NAND pages with unstable bits -
re-reading may help to get correct data.

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

UBI: use raw mtd read function in debugging code

This change affects only the debugging code. Namely, use mtd->read()
function instead of ubi_io_read() to avoid bit-flips injection
(ubi_dbg_is_bitflip()) which we do not want on the debugging path.

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

UBI: try to reveal buggy MTD drivers

When reading data from the flash, corrupt the buffer we are about to
read to. The idea is to fix the following possible situation:

1. The buffer contains data from previous operation, e.g., read from
another PEB previously. The data looks like expected, e.g., if we
just do not read anything and return - the caller would not
notice this. E.g., if we are reading a VID header, the buffer may
contain a valid VID header from another PEB.
2. The driver is buggy and returns use success or -EBADMSG or
-EUCLEAN, but it does not actually put any data to the buffer.

This may confuse UBI or upper layers - they may think the buffer
contains valid data while in fact it is just old data.

Thus, try to reveal such buggy MTD drivers with simple debugging
code which fills the read buffer with 0x12 constant.

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

UBI: add a commentary about allocating VID header buffer on stack

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

UBI: fix NOR erase preparation quirk

In 'nor_erase_prepare()' we want to make sure the UBI headers are
corrupted. But it is possible that one of the headers just contains
all 0xFFs, which is also OK, because UBI will erase it in case of
a power cut.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: fix corrupted PEB detection for NOR flash

My new shiny code for corrupted PEB detection has NOR specific bug.
We tread PEB as corrupted and preserve it, if

1. EC header is OK.
2. VID header is corrupted.
3. data area is not "all 0xFFs"

In case of NOR we have 'nor_erase_prepare()' quirk, which invalidates
the headers before erasing the PEB. And we invalidate first the VID
header, and then the EC header. So if a power cut happens after we have
invalidated the VID header, but before we have invalidated the EC
header, we end up with a PEB which satisfies the above 3 conditions,
and the scanning code will treat it as corrupted, and will print
scary warnings, wrongly.

This patch fixes the issue by firt invalidating the EC header, then
invalidating the VID header. In case of power cut inbetween, we still
just lose the EC header, and UBI can deal with this situation gracefully.

Thanks to Anatolij Gustschin <agust@denx.de> for tracking this down.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reported-by: Anatolij Gustschin <agust@denx.de>
Tested-by: Anatolij Gustschin <agust@denx.de>

UBI: make check_pattern function non-static

This patch turns static function 'check_pattern()' into a non-static
'ubi_check_pattern()'. This is just a preparation for the chages which
are coming in the next patches.

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

UBI: handle bit-flips when no header found

Currently UBI has one small flaw - when we read EC or VID header, but find only
0xFF bytes, we return UBI_IO_FF and do not report whether we had bit-flips or
not. In case of the VID header, the scanning code adds this PEB to the free list,
even though there were bit-flips.

Imagine the following situation: we start writing VID header to a PEB and have a
power cut, so the PEB becomes unstable. When we scan and read the PEB, we get
a bit-flip. Currently, UBI would just ignore this and treat the PEB as free. This
patch changes UBI behavior and now UBI will schedule this PEB for erasure.

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

UBI: remove duplicate IO error codes

The 'UBI_IO_PEB_EMPTY' and 'UBI_IO_PEB_FREE' are essentially the same
and mean that there are only 0xFF bytes instead of headers. Simplify
UBI a little by turning them into a single 'UBI_IO_FF' error code.

Also, stop maintaining commentaries in 'ubi_io_read_vid_hdr()' which are
almost identical to commentaries in 'ubi_io_read_ec_hdr()'.

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

UBI: rename IO error code

Rename UBI_IO_BAD_HDR_READ into UBI_IO_BAD_HDR_EBADMSG which is presumably more
self-documenting and readable. Indeed, the '_READ' suffix does not tell much and
even confuses, while '_EBADMSG' tells about uncorrectable ECC error, because we
use -EBADMSG all over the place to represent ECC errors.

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

UBI: fix error message and compilation warnings

Fix the followong compilation warnings introduced by commit
095751a6e0838a712393a74eb0b7b6559dbdbe81:

drivers/mtd/ubi/scan.c: In function 'check_what_we_have':
drivers/mtd/ubi/scan.c:960: warning: passing argument 1 of 'get_random_bytes' discards qualifiers from pointer target type

Fix the following compilation warnings introduced by commit
1a49af2ca019dcb4614c32f832bbcb814b61409c:

drivers/mtd/ubi/io.c: In function 'ubi_io_read':
drivers/mtd/ubi/io.c:153: warning: initialization makes integer from pointer without a cast
drivers/mtd/ubi/io.c:170: warning: format '%s' expects type 'char *', but argument 5 has type 'int'
drivers/mtd/ubi/io.c:177: warning: format '%zd' expects type 'signed size_t', but argument 7 has type 'int'
drivers/mtd/ubi/io.c:177: warning: too many arguments for format

Also, amend the ECC error code string and add brackets and whitespace
there - this should make the message readable.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: improve ECC error message

ECC errors are quite typical errors on NAND, so it is worth improving
the UBI message and print something like

ubi_io_read: error -74 (ECC error) while reading 4096 bytes from PEB 1:4 ...

rather than

ubi_io_read: error -74 while reading 4096 bytes from PEB 1:4 ...

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

UBI: introduce a new IO return code

This patch introduces the %UBI_IO_BAD_HDR_READ return code for
the I/O level function. We will use this code in order to distinguish
between "corrupted header possibly because this is non-ubi data" and
"corrupted header possibly because of real data corruption and ECC error".

So far this patch does not introduce any functional change, just a
preparation.

This patch is pased on a patch from
Sebastian Andrzej Siewior <sebastian@breakpoint.cc>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Tested-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>

UBI: simplify IO error codes

We do not really need 2 separate error codes for indicating bad VID
and bad EC headers (UBI_IO_BAD_EC_HDR, UBI_IO_BAD_VID_HDR), it is
enough to have only one UBI_IO_BAD_HDR return code.

This patch does not introduce any functional change, only some
code simplification.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Tested-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>

UBI: misc comment fixes

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: fix s/then/than/ typos

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

UBI: add write checking

Add an extra debugging check function which validates writes.
After every write it reads the data back, compares it with the
original data, and complains if they mismatch.

Useful for debugging. No-op if extra debugging checks are disabled.

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

UBI: simplify debugging return codes

UBI debugging functions were a little bit over-engineered and
returned more error codes than needed, and the callers had to
do useless checks. Simplify the return codes.

Impact: only debugging code is affected, which means that for
non-developers this is a no-op patch.

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

UBI: improve NOR flash erasure quirk

More testing of NOR flash against power cuts showed that sometimes
eraseblocks may be unwritable, and we cannot really invalidate
them before erasure. But in this case the eraseblock probably
contains garbage anyway, and we do not have to invalidate the
headers. This assumption might be not true, but this is at least
what I have observed. So if we cannot invalidate the headers,
we make sure that the PEB does not contain valid VID header.
If this is true, everything is fine, otherwise we panic.

UBI: introduce flash dump helper

Useful for debugging problems, compiled in only if UBI debugging
is enabled. This patch also makes the UBI writing function dump
the flash if it fails to write.

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

UBI: amend NOR flash pre-erase quirk

In case of NOR flash, UBI zeroes EC and VID headers' magic,
in order to detect interrupted erasures. It first zeroes out
the EC magic, then VID magic. However, if a power cut happens
in between, we'll end up with a corrupted EC header and a valid
VID header, in which case UBI accepts the PEB, but prints a
warning. This patch makes sure we first zero out the VID
magic, then the EC magic, not vice versa. This is just a
small amendment to prevent warning messages.

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

UBI: fix compilation warnings

The recent "UBI: fix NOR flash recovery" introduced compilation
warnings which were immediately spotted by our linux-next keeper.
This patch fixes them.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: fix NOR flash recovery

This commit fixes NOR flash recovery issues observed with Spansion
S29GL512N NOR.

When NOR erases, it first fills PEBs with zeroes, then sets all bytes
to 0xFF. Filling with zeroes starts from the end of the PEB. And when
power is cut, this results in PEBs containing correct EC and VID headers
but corrupted with zeros at the end. This confuses UBI and it mistakinly
accepts these PEBs and associate them with LEBs.

Fis this issue by zeroing EC and VID magics before erasing PEBs, to
make UBI later refuse zem.

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

UBI: nicify image sequence number handling

Move the image seq. number handling from I/O level to the scanning
lever, where it really belongs to. Move the @image_seq_set variable
to the @struct ubi_scan_info structure, which exists only during
scanning.

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

UBI: add image sequence number to EC header

An image sequence number is added to the UBI erase-counter header
to be able determine if the root file system contains a mixture
of old and new images (because the flashing failed to complete).

A change to nolo is also needed for this to take effect.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: remove bogus debugging checks

The 'paranoid_check_empty()' is bogus because, which is easilly
seen on NOR flash, which has long erase cycles, and which may
easilly end-up with half-erased eraseblocks. In this case the
paranoid check fails. I is just wrong to assume that PEBs which
do not have EC headers always contain all 0xFF. Such assumption
should not be made on the I/O level, which is quite low.

Thus, just kill the check.

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

UBI: add empty eraseblocks verification

This patch adds code which makes sure eraseblocks contain all 0xFF
bytes before starting using them. The verification is done only when
debugging checks are enabled.

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

UBI: fix multiple spelling typos

Some of the typos were indicated by Adrian Hunter,
some by 'aspell'.

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

UBI: fix races in I/O debugging checks

When paranoid checs are enabled, the 'io_paral' test from the
'mtd-utils' package fails. The symptoms are:

UBI error: paranoid_check_all_ff: flash region at PEB 3973:512, length 15872 does not contain all 0xFF bytes
UBI error: paranoid_check_all_ff: paranoid check failed for PEB 3973
UBI: hex dump of the 512-16384 region

It turned out to be a bug in the checking function. Suppose there
are 2 tasks - A and B. Task A is the wear-levelling working
('wear_leveling_worker()'). It is reading the VID header to find
which LEB this PEB belongs to. Say, task A is reading header
of PEB X. Suppose PEB X is unmapped, and has no VID header.
Task B is trying to write to PEB X.

Task A: in 'ubi_io_read_vid_hdr()': reads the VID header from PEB X.
The read data contain all 0xFF bytes.
Task B: writes VID header and some data to PEB X
Task A: assumes PEB X is empty, calls 'paranoid_check_all_ff()', which
fails.

The solution for this problem is to make 'paranoid_check_all_ff()'
re-read the VID header, re-check it, and only if it is not there,
check the rest. This now implemented by the 'paranoid_check_empty()'
function.

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

trivial: fix then -> than typos in comments and documentation

- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

UBI: fix checkpatch.pl warnings

Just minor indentation and "over 80 characters" fixes.

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

UBI: fix warnings when debugging is enabled

The 'ubi_io_read_vid_hdr()' and 'ubi_io_read_ec_hdr()' function
have the 'verbose' argument which controls whether they should
print a warning if the VID/EC header was not found or was corrupted.
Some callers require the headers to be OK, and pass 1. Some allow
a corrupted/not present header, and pass 0.

if (UBI_IO_DEBUG)
verbose = 1;

And UBI_IO_DEBUG is 1 if CONFIG_MTD_UBI_DEBUG_MSG_BLD is true. So in
this case the warning is printed all the time. This confuses people.

Thus, do not print the messages as warnings if UBI_IO_DEBUG is true,
but print them as debugging messages instead.

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

UBI: fix kernel-doc errors and warnings

No functional changes, just tweak comments to make kernel-doc
work fine and stop complaining.

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

UBI: fix checkpatch.pl errors and warnings

Just out or curiousity ran checkpatch.pl for whole UBI,
and discovered there are quite a few of stylistic issues.
Fix them.

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

UBI: rework scrubbing messages

If bit-flips happen often, UBI prints to many messages. Lessen
the amount by only printing the messages when the PEB has been
scrubbed. Also, print torturing messages.

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

UBI: fix and re-work debugging stuff

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

UBI: amend commentaries

Hch asked not to use "unit" for sub-systems, let it be so.
Also some other commentaries modifications.

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

UBI: be verbose when debuggin is enabled

Make I/O function to be always verbose when about CRC errors
and magic number errors when I/O debugging is enabled.

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

UBI: fix error code in ubi_io_read()

When NAND detects an ECC error, it returns -EBADMSG. It does not
stop reading requested data if one page has an ECC error, it keeps
going and reads all the requested data. If it fails to read all
the data, it does not return -EBADMSG, but returns the error code
which reflects the reason of the failure.

But some drivers may have bugs (e.g., OneNAND had) and stop reading
after the first ECC error, so it returns -EBADMSG. In turn, UBI
propagates this up to the caller. The caller will treat this as
"all the requested data was read, but there was an ECC error".

So we change the error code to -EIO if it is -EBADMSG and the read
length is less then the requested length. We also add an assertion,
so if UBI debugging is enabled, UBI will bug.

Pointed-to-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: use byte hexdump

More handy since word hexdump prints in host endian.

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

UBI: do not use vmalloc on I/O path

Similar reason as in case of the previous patch: it causes
deadlocks if a filesystem with writeback support works on top
of UBI. So pre-allocate needed buffers when attaching MTD device.
We also need mutexes to protect the buffers, but they do not
cause much contantion because they are used in recovery, torture,
and WL copy routines, which are called seldom.

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

UBI: allocate memory with GFP_NOFS

Use GFP_NOFS flag when allocating memory on I/O path, because otherwise
we may deadlock the filesystem which works on top of us. We observed
the deadlocks with UBIFS. Example:

VFS->FS lock a lock->UBI->kmalloc()->VFS writeback->FS locks the same
lock again.

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

UBI: use linux print_hex_dump(), not home-grown one

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

UBI: add more prints

I hit those situations and found out lack of print messages. Add more prints
when erase problems occur.

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

UBI: fix comments

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

UBI: fix signed-unsigned multiplication

There is signed multiplication assigned to unsigned ei.addr in io.c.
This causes wrong addresses for big multiplication.This patch solves the
problem.

Signed-off-by: Brijesh Singh <brijesh.s.singh@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: kill homegrown endian macros

Kill UBI's homegrown endianess handling and replace it with
the standard kernel endianess handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI: use vmalloc for large buffers

UBI allocates temporary buffers of PEB size, which may be 256KiB.
Use vmalloc instead of kmalloc for such big temporary buffers.

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

UBI: Unsorted Block Images

UBI (Latin: "where?") manages multiple logical volumes on a single
flash device, specifically supporting NAND flash devices. UBI provides
a flexible partitioning concept which still allows for wear-levelling
across the whole flash device.

In a sense, UBI may be compared to the Logical Volume Manager
(LVM). Whereas LVM maps logical sector numbers to physical HDD sector
numbers, UBI maps logical eraseblocks to physical eraseblocks.

More information may be found at
http://www.linux-mtd.infradead.org/doc/ubi.html

Partitioning/Re-partitioning

An UBI volume occupies a certain number of erase blocks. This is
limited by a configured maximum volume size, which could also be
viewed as the partition size. Each individual UBI volume's size can
be changed independently of the other UBI volumes, provided that the
sum of all volume sizes doesn't exceed a certain limit.

UBI supports dynamic volumes and static volumes. Static volumes are
read-only and their contents are protected by CRC check sums.

Bad eraseblocks handling

UBI transparently handles bad eraseblocks. When a physical
eraseblock becomes bad, it is substituted by a good physical
eraseblock, and the user does not even notice this.

Scrubbing

On a NAND flash bit flips can occur on any write operation,
sometimes also on read. If bit flips persist on the device, at first
they can still be corrected by ECC, but once they accumulate,
correction will become impossible. Thus it is best to actively scrub
the affected eraseblock, by first copying it to a free eraseblock
and then erasing the original. The UBI layer performs this type of
scrubbing under the covers, transparently to the UBI volume users.

Erase Counts

UBI maintains an erase count header per eraseblock. This frees
higher-level layers (like file systems) from doing this and allows
for centralized erase count management instead. The erase counts are
used by the wear-levelling algorithm in the UBI layer. The algorithm
itself is exchangeable.

Booting from NAND

For booting directly from NAND flash the hardware must at least be
capable of fetching and executing a small portion of the NAND
flash. Some NAND flash controllers have this kind of support. They
usually limit the window to a few kilobytes in erase block 0. This
"initial program loader" (IPL) must then contain sufficient logic to
load and execute the next boot phase.

Due to bad eraseblocks, which may be randomly scattered over the
flash device, it is problematic to store the "secondary program
loader" (SPL) statically. Also, due to bit-flips it may become
corrupted over time. UBI allows to solve this problem gracefully by
storing the SPL in a small static UBI volume.

UBI volumes vs. static partitions

UBI volumes are still very similar to static MTD partitions:

* both consist of eraseblocks (logical eraseblocks in case of UBI
volumes, and physical eraseblocks in case of static partitions;
* both support three basic operations - read, write, erase.

But UBI volumes have the following advantages over traditional
static MTD partitions:

* there are no eraseblock wear-leveling constraints in case of UBI
volumes, so the user should not care about this;
* there are no bit-flips and bad eraseblocks in case of UBI volumes.

So, UBI volumes may be considered as flash devices with relaxed
restrictions.

Where can it be found?

Documentation, kernel code and applications can be found in the MTD
gits.

What are the applications for?

The applications help to create binary flash images for two purposes: pfi
files (partial flash images) for in-system update of UBI volumes, and plain
binary images, with or without OOB data in case of NAND, for a manufacturing
step. Furthermore some tools are/and will be created that allow flash content
analysis after a system has crashed..

Who did UBI?

The original ideas, where UBI is based on, were developed by Andreas
Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and some others
were involved too. The implementation of the kernel layer was done by Artem
B. Bityutskiy. The user-space applications and tools were written by Oliver
Lohmann with contributions from Frank Haverkamp, Andreas Arnez, and Artem.
Joern Engel contributed a patch which modifies JFFS2 so that it can be run on
a UBI volume. Thomas Gleixner did modifications to the NAND layer. Alexander
Schmidt made some testing work as well as core functionality improvements.

Signed-off-by: Artem B. Bityutskiy <dedekind@linutronix.de>
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>