We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20211103230437.1639990-10-mcgrof@kernel.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The snprintf() function returns the number of characters (not
counting the NUL terminator) that it would have printed if we
had space.

This buffer has UBIFS_DFS_DIR_LEN characters plus one extra for
the terminator.  Printing UBIFS_DFS_DIR_LEN is okay but anything
higher will result in truncation.  Thus the comparison needs to be
change from == to >.

These strings are compile time constants so this patch doesn't
affect runtime.

Fixes: ae380ce0 ("UBIFS: lessen the size of debugging info data structure")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alexander Dahl <ada@thorsis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-27-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

struct ubi_wl_entry is defined at 178th line.
The declaration here is unnecessary. Remove it.

Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115


Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

The parameter of kfree function is NULL, so kfree code is useless, delete it.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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>

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>

As a local variable, "endp" is neither refered nor returned
after this line "endp += 2", it looks like a useless code,
suggest to remove it.

Signed-off-by: Chengsong Ke <kechengsong@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Fixes the following W=1 kernel build warning(s):

 drivers/mtd/ubi/gluebi.c:446: warning: Function parameter or member 'ns_ptr' not described in 'gluebi_notify'
 drivers/mtd/ubi/gluebi.c:446: warning: Excess function parameter 'ptr' description in 'gluebi_notify'

Cc: Richard Weinberger <richard@nod.at>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-15-lee.jones@linaro.org

Fixes the following W=1 kernel build warning(s):

 drivers/mtd/ubi/wl.c:584: warning: Function parameter or member 'nested' not described in 'schedule_erase'
 drivers/mtd/ubi/wl.c:1075: warning: Excess function parameter 'shutdown' description in '__erase_worker'

Cc: Richard Weinberger <richard@nod.at>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-13-lee.jones@linaro.org

Fixes the following W=1 kernel build warning(s):

 drivers/mtd/ubi/eba.c:1304: warning: Function parameter or member 'vidb' not described in 'ubi_eba_copy_leb'
 drivers/mtd/ubi/eba.c:1304: warning: Excess function parameter 'vid_hdr' description in 'ubi_eba_copy_leb'
 drivers/mtd/ubi/eba.c:1483: warning: Function parameter or member 'ai' not described in 'print_rsvd_warning'

Cc: Richard Weinberger <richard@nod.at>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-12-lee.jones@linaro.org

Fixes the following W=1 kernel build warning(s):

 drivers/mtd/ubi/kapi.c:464: warning: Function parameter or member 'sgl' not described in 'ubi_leb_read_sg'
 drivers/mtd/ubi/kapi.c:464: warning: Excess function parameter 'buf' description in 'ubi_leb_read_sg'

Cc: Richard Weinberger <richard@nod.at>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-11-lee.jones@linaro.org

Fixes the following W=1 kernel build warning(s):

 drivers/mtd/ubi/build.c:61: warning: Function parameter or member 'ubi_num' not described in 'mtd_dev_param'

Cc: Richard Weinberger <richard@nod.at>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-9-lee.jones@linaro.org

A detach hung is possible when a race occurs between the detach process
and the ubi background thread. The following sequences outline the race:

  ubi thread: if (list_empty(&ubi->works)...

  ubi detach: set_bit(KTHREAD_SHOULD_STOP, &kthread->flags)
              => by kthread_stop()
              wake_up_process()
              => ubi thread is still running, so 0 is returned

  ubi thread: set_current_state(TASK_INTERRUPTIBLE)
              schedule()
              => ubi thread will never be scheduled again

  ubi detach: wait_for_completion()
              => hung task!

To fix that, we need to check kthread_should_stop() after we set the
task state, so the ubi thread will either see the stop bit and exit or
the task state is reset to runnable such that it isn't scheduled out
indefinitely.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Cc: <stable@vger.kernel.org>
Fixes: 801c135c ("UBI: Unsorted Block Images")
Reported-by:  <syzbot+853639d0cb16c31c7a14@syzkaller.appspotmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi_wl_entry related with the fm_next_anchor PEB is not freed during
detach, which causes a memory leak.
Don't forget to release fm_next_anchor PEB while detaching ubi from
mtd when CONFIG_MTD_UBI_FASTMAP is enabled.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Fixes: 4b68bf9a ("ubi: Select fastmap anchor PEBs considering...")
Signed-off-by: Richard Weinberger <richard@nod.at>

Following process triggers a memleak caused by forgetting to release the
initial next anchor PEB (CONFIG_MTD_UBI_FASTMAP is disabled):
1. attach -> __erase_worker -> produce the initial next anchor PEB
2. detach -> ubi_fastmap_close (Do nothing, it should have released the
   initial next anchor PEB)

Don't produce the initial next anchor PEB in __erase_worker() when fastmap
is disabled.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Suggested-by: Sascha Hauer <s.hauer@pengutronix.de>
Fixes: f9c34bb5 ("ubi: Fix producing anchor PEBs")
Reported-by:  <syzbot+d9aab50b1154e3d163f5@syzkaller.appspotmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/



Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>

The include/linux/pgtable.h is going to be the home of generic page table
manipulation functions.

Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and
make the latter include asm/pgtable.h.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is a risk that the fastmap anchor PEB is alternating between
just two PEBs, the current anchor and the previous anchor that was just
deleted. As the fastmap pools gets the first take on free PEBs, the
pools may leave no free PEBs to be selected as the new anchor,
resulting in the two PEBs alternating behaviour. If the anchor PEBs gets
a high erase count the PEBs will not be used by the pools but remain in
ubi->free, even more increasing the likelihood they will be used as
anchors.

Getting stuck using only a couple of PEBs continuously will result in an
uneven wear, eventually leading to failure.

To fix this:

- Choose the fastmap anchor when the most free PEBs are available. This is
  during rebuilding of the fastmap pools, after the unused pool PEBs are
  added to ubi->free but before the pools are populated again from the
  free PEBs. Also reserve an additional second best PEB as a candidate
  for the next time the fast map anchor is updated. If a better PEB is
  found the next time the fast map anchor is updated, the candidate is
  made available for building the pools.

- Enable anchor move within the anchor area again as it is useful for
  distributing wear.

- The anchor candidate for the next fastmap update is the most suited free
  PEB. Check this PEB's erase count during wear leveling. If the wear
  leveling limit is exceeded, the PEB is considered unsuitable for now. As
  all other non used anchor area PEBs should be even worse, free up the
  used anchor area PEB with the lowest erase count.

Signed-off-by: Arne Edholm <arne.edholm@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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>

3bfa7e14 ("fs/seq_file.c: seq_read(): add info message about buggy .next functions")
showed that we don't use seq_file correctly.
So make sure that our ->next function always updates the position.

Fixes: 7bccd12d ("ubi: Add debugfs file for tracking PEB state")
Signed-off-by: Richard Weinberger <richard@nod.at>

The MTD layer provides an SLC mode (purely software emulation of SLC
behavior) addressing the paired-pages corruption issue, which was the
main reason for refusing attaching MLC NANDs to UBI.

Relax this rule and allow partitions that have the
MTD_EMULATE_SLC_ON_MLC flag set to be attached.

Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/linux-mtd/20200503155341.16712-9-miquel.raynal@bootlin.com

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21


[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Don't produce the initial anchor PEB when ubi device is read-only
or fastmap is disabled, else the resulting PEB will be unusable
to any volume.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

When CONFIG_MTD_UBI_FASTMAP is enabled, fm_anchor will be assigned
a free PEB during ubi_wl_init() or ubi_update_fastmap(). However
if fastmap is not used or disabled on the MTD device, ubi_wl_entry
related with the PEB will not be freed during detach.

So Fix it by freeing the unused fastmap anchor during detach.

Fixes: f9c34bb5 ("ubi: Fix producing anchor PEBs")
Reported-by:  <syzbot+f317896aae32eb281a58@syzkaller.appspotmail.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Use Joe Perches cvt_fallthrough.pl script to convert

	/* fallthrough */

comments (and its derivatives) into a

	fallthrough;

statement. This automatically drops useless ones.

Do it MTD-wide.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Vignesh Raghavendra <vigneshr@ti.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/linux-mtd/20200325212115.14170-1-miquel.raynal@bootlin.com

'PTR_ERR(p) == -E*' is a stronger condition than IS_ERR(p).
Hence, IS_ERR(p) is unneeded.

The semantic patch that generates this commit is as follows:

// <smpl>
@@
expression ptr;
constant error_code;
@@
-IS_ERR(ptr) && (PTR_ERR(ptr) == - error_code)
+PTR_ERR(ptr) == - error_code
// </smpl>

Link: http://lkml.kernel.org/r/20200106045833.1725-1-masahiroy@kernel.org


Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Stephen Boyd <sboyd@kernel.org> [drivers/clk/clk.c]
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> [GPIO]
Acked-by: Wolfram Sang <wsa@the-dreams.de> [drivers/i2c]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [acpi/scan.c]
Acked-by: Rob Herring <robh@kernel.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If "seen_pebs = init_seen(ubi);" fails then "seen_pebs" is an error pointer
and we try to kfree() it which results in an Oops.

This patch re-arranges the error handling so now it only frees things
which have been allocated successfully.

Fixes: daef3dd1 ("UBI: Fastmap: Add self check to detect absent PEBs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

The allocated normal volumes saved in ubi->volumes are not freed
in the error paths in ubi_attach_mtd_dev() and its callees (e.g.
ubi_attach() and ubi_read_volume_table()).

These normal volumes should be freed through kill_volumes() and
vol_release(), but ubi_attach_mtd_dev() may fail before
calling uif_init(), and there will be memory leaks.

So adding a new helper ubi_free_all_volumes() to free the normal
and the internal volumes. And in order to prevent double-free
of volume, reset ubi->volumes[i] to NULL after freeing.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Else there may be oops when fastmap is enabled and init_volumes() fails.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/mtd/ubi/wl.c: In function 'find_wl_entry':
drivers/mtd/ubi/wl.c:322:27: warning:
 variable 'prev_e' set but not used [-Wunused-but-set-variable]

It's not used any more now, so remove it.

Fixes: f9c34bb5 ("ubi: Fix producing anchor PEBs")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

set_seen() sets the bit corresponding to the PEB number in the bitmap,
so when self_check_seen() wants to find PEBs that haven't been seen we
have to print the PEBs that have their bit cleared, not the ones which
have it set.

Fixes: 5d71afb0 ("ubi: Use bitmaps in Fastmap self-check code")
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

When a new fastmap is about to be written UBI must make sure it has a
free block for a fastmap anchor available. For this ubi_update_fastmap()
calls ubi_ensure_anchor_pebs(). This stopped working with 2e8f08de
("ubi: Fix races around ubi_refill_pools()"), with this commit the wear
leveling code is blocked and can no longer produce free PEBs. UBI then
more often than not falls back to write the new fastmap anchor to the
same block it was already on which means the same erase block gets
erased during each fastmap write and wears out quite fast.

As the locking prevents us from producing the anchor PEB when we
actually need it, this patch changes the strategy for creating the
anchor PEB. We no longer create it on demand right before we want to
write a fastmap, but instead we create an anchor PEB right after we have
written a fastmap. This gives us enough time to produce a new anchor PEB
before it is needed. To make sure we have an anchor PEB for the very
first fastmap write we call ubi_ensure_anchor_pebs() during
initialisation as well.

Fixes: 2e8f08de ("ubi: Fix races around ubi_refill_pools()")
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

Compiler generates following warning when kernel is built with W=1:

drivers/mtd/ubi/ubi.h:971:1: warning: ‘static’ is not at beginning
of declaration [-Wold-style-declaration]

This commit fixes this by correctly ordering keywords.

Signed-off-by: Rishi Gupta <gupt21@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

It might be interesting, if "skip_check" is set or not, so lets print
this flag in ubi_dump_vol_info() as well.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Heiko Schocher <hs@denx.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Each of these drivers has a copy of the same trivial helper function to
convert the pointer argument and then call the native ioctl handler.

We now have a generic implementation of that, so use it.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

If volume size is not a multiple of 512, ubi block cuts
off the last bytes of an volume since the block layer works
on 512 byte sectors.
This can happen especially on NOR flash with minimal io
size of 1.

To avoid unpleasant surprises, print a warning.

Signed-off-by: Richard Weinberger <richard@nod.at>

Running stress test io_paral (A pressure ubi test in mtd-utils) on an
UBI device with fewer PEBs (fastmap enabled) may cause ENOSPC errors and
make UBI device read-only, but there are still free PEBs on the UBI
device. This problem can be easily reproduced by performing the following
steps on a 2-core machine:
  $ modprobe nandsim first_id_byte=0x20 second_id_byte=0x33 parts=80
  $ modprobe ubi mtd="0,0" fm_autoconvert
  $ ./io_paral /dev/ubi0

We may see the following verbose:
(output)
  [io_paral] update_volume():108: failed to write 380 bytes at offset
  95920 of volume 2
  [io_paral] update_volume():109: update: 97088 bytes
  [io_paral] write_thread():227: function pwrite() failed with error 28
  (No space left on device)
  [io_paral] write_thread():229: cannot write 15872 bytes to offs 31744,
  wrote -1
(dmesg)
  ubi0 error: ubi_wl_get_peb [ubi]: Unable to get a free PEB from user WL
  pool
  ubi0 warning: ubi_eba_write_leb [ubi]: switch to read-only mode
  CPU: 0 PID: 2027 Comm: io_paral Not tainted 5.3.0-rc2-00001-g5986cd0 #9
  ubi0 warning: try_write_vid_and_data [ubi]: failed to write VID header
  to LEB 2:5, PEB 18
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0
  -0-ga698c8995f-prebuilt.qemu.org 04/01/2014
  Call Trace:
    dump_stack+0x85/0xba
    ubi_eba_write_leb+0xa1e/0xa40 [ubi]
    vol_cdev_write+0x307/0x520 [ubi]
    vfs_write+0xfa/0x280
    ksys_pwrite64+0xc5/0xe0
    __x64_sys_pwrite64+0x22/0x30
    do_syscall_64+0xbf/0x440

In function ubi_wl_get_peb, the operation of filling the pool
(ubi_update_fastmap) with free PEBs and fetching a free PEB from the pool
is not atomic. After thread A filling the pool with free PEB, free PEB may
be taken away by thread B. When thread A checks the expression again, the
condition is still unsatisfactory. At this time, there may still be free
PEBs on UBI that can be filled into the pool.

This patch increases the number of attempts to obtain PEB. An extreme
case (No free PEBs left after creating test volumes) has been tested on
different type of machines for 100 times. The biggest number of attempts
are shown below:

             x86_64     arm64
  2-core        4         4
  4-core        8         4
  8-core        4         4

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