The Renesas BSP confirms that H3 ES1.x and M3-W ES1.[012] do not
properly support HS400. Add a quirk to indicate this and disable HS400
in the MMC capabilities if the quirk is set.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

It was though all ES revisions of H3 and M3-W SoCs required the
TMIO_MMC_HAVE_4TAP_HS400 flag. Recent datasheet updates tells us this is
not true, only early ES revisions of the SoC do.

Since quirk matching based on ES revisions is now used to handle the
flag it's possible to align all Gen3 compatibility properties. This will
allow later ES revisions of H3 and M3-W to use the correct 8-tap HS400
mode.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Latest datasheet makes it clear that not all ES revisions of the H3 and
M3-W have the 4-tap HS400 mode quirk, currently the quirk is set
unconditionally for these two SoCs. Prepare to handle the quirk based on
SoC revision instead of compatibility value by using soc_device_match()
and set the TMIO_MMC_HAVE_4TAP_HS400 flag explicitly.

The reason for adding a new quirks struct instead of just a flag is that
looking ahead it seems more quirks needs to be handled in a SoC revision
basis.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The initial value of the interrupt mask register may be different from
the H/W manual at the startup of the kernel by setting from the
bootloader. Since the error interrupts may be unmasked, the driver sets
initial value.

The initial value is only known for R-Car Gen2 and Gen3 platforms so
limit the initialization to those platforms.

Based on work from Masaharu Hayakawa.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

SD / MMC did not operate properly when suspend transition failed.
Because the SCC was not reset at resume, issue of the command failed.
Call the host specific reset function and reset the hardware in order to
add reset of SCC. This change also fixes tuning on some stubborn cards
on Gen2.

Based on work from Masaharu Hayakawa.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

On runtime power management resume, the host clock needs to be
enabled before calling tmio_mmc_reset. If the mmc device has a power
domain entry, the host clock is enabled via genpd_runtime_resume,
running before tmio_mmc_host_runtime_resume. If the mmc device has no
power domain entry, however, genpd_runtime_resume is not called. This
patch changes tmio_mmc_host_runtime_resume to enable the host clock
before calling tmio_mmc_reset.

Based on work from Masaharu Hayakawa.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The only user was converted to fill a sbc command which is the proper
way to do it because of AutoCMD23 feature of some hosts.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Clément Péron <peron.clem@gmail.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

In case dmaengine_prep_slave_sg fails we need to call dma_unmap_sg.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

There are two variables len within bcm2835_prepare_dma. So rename the
result of dma_map_sg to sg_len. While we are at this add a bail out to
simplify the following change.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

It's better to make sure that the timeout work is really terminated
before calling mmc_request_done.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

There are two accesses on the data requests which are not protected by
the mutex. So fix this accordingly.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

We need to release the slave DMA channel during driver unload.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

If the user issues an "mmc extcsd read", the SD controller receives
what it thinks is a SEND_IF_COND command with an unexpected data block.
The resulting operations leave the FSM stuck in READWAIT, a state which
persists until the MMC framework resets the controller, by which point
the root filesystem is likely to have been unmounted.

A less heavyweight solution is to detect the condition and nudge the
FSM by asserting the (self-clearing) FORCE_DATA_MODE bit.

Link: https://github.com/raspberrypi/linux/issues/2728Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The bcm2835 mmc host tends to lock up for unknown reason so reset it on
timeout. The upper mmc block layer tries retransimitting with single
blocks which tends to work out after a long wait.

This is better than giving up and leaving the machine broken for no
obvious reason.

Fixes: 660fc733 ("mmc: bcm2835: Add new driver for the sdhost controller.")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Simplify things by making the i.MX SDHCI driver just use
slot GPIO with descriptors instead of passing around the global
GPIO numbers that we want to get rid of.

As it turns out, just one single board is using the platform
data to pass in GPIOs numbers for CD and WP, so we augment this
to use a machine descriptor table instead.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The power GPIO line is passed with inversion flags and all from
the platform data. Switch to using an optional GPIO descriptor and
use this to switch the power.

Augment the only boardfile to pass in the proper "power" descriptor
in the GPIO descriptor machine table instead.

As the GPIO handling is now much simpler, we can cut down on some
overhead code.

Cc: Paul Cercueil <paul@crapouillou.net>
Cc: linux-mips@linux-mips.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Modifty the JZ4740 driver to retrieve card detect and write
protect GPIO pins from GPIO descriptors instead of hard-coded
global numbers. Augment the only board file using this in the
process and cut down on passed in platform data.

Preserve the code setting the caps2 flags for CD and WP
as active low or high since the slot GPIO code currently
ignores the gpiolib polarity inversion semantice and uses
the raw accessors to read the GPIO lines, but set the right
polarity flags in the descriptor table for jz4740.

Cc: Paul Cercueil <paul@crapouillou.net>
Cc: linux-mips@linux-mips.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The use of string pointers in the MMC slot GPIO context is
pretty dubious, allocating some 2*len extra bytes for each
label of the ro and wp pins.

Tidy this up using kasprintf() with dynamic allocation of
labels for these strings.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

On few SDHCI-MSM controllers, the host controller's clock tuning
circuit may go out of sync if controller clocks are gated which
eventually will result in data CRC, command CRC/timeout errors.
To overcome this h/w limitation, the DLL needs to be re-initialized
and restored with its old settings once clocks are ungated.
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Add SoC-specific compatible strings for qcom-sdhci controller.
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

If the host controller supports auto-commands then enable the auto-command
error interrupt and handle it. In the case of auto-CMD23, the error is
treated the same as manual CMD23 error. In the case of auto-CMD12,
commands-during-transfer are not permitted, so the error handling is
treated the same as a data error.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The SDHCI_ACMD12_ERR register is used for auto-CMD23 and auto-CMD12
errors, as is the SDHCI_INT_ACMD12ERR interrupt bit. Rename them to
SDHCI_AUTO_CMD_STATUS and SDHCI_INT_AUTO_CMD_ERR respectively.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Existing data command CRC error handling is non-standard and does not work
with some Intel host controllers. Specifically, the assumption that the host
controller will continue operating normally after the error interrupt,
is not valid. Change the driver to handle the error in the same manner
as a data CRC error, taking care to ensure that the data line reset is
done for single or multi-block transfers, and it is done before
unmapping DMA.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Adopt the SPDX license identifier headers to ease license compliance
management.

Cc: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Whitelist R8A77990 E3 SoC in the SDHI driver. The SDHI core
present in the SoC is an 8tap variant of the Gen3 SDHI core.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-renesas-soc@vger.kernel.org
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The manual does not contain information that a wait is needed in the
tuning process, this might be a leftover from early development.
Removing the wait don't have any effect on operation so delete the wait
to shorten the initialization time.
Signed-off-by: Masaharu Hayakawa <masaharu.hayakawa.ry@renesas.com>
Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
[Niklas: fixup commit message]
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The driver sets an incorrect clock and depends on the clock driver
knowledge of this incorrect setting to still set a 200Mhz SDn clock.
Instead of spreading the workaround between the two drivers the clock
driver should be made aware of the ES versions where the special clock
handling is needed no need to keep this workaround in the SDHI driver.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The reason of including <linux/bitops.h> here is just for BIT() and
GENMASK() macros.

Since commit 8bd9cb51 ("locking/atomics, asm-generic: Move some
macros from <linux/bitops.h> to a new <linux/bits.h> file"),
<linux/bits.h> is enough for such compile-time macros.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The function sdhci_allocate_bounce_buffer() always return zero at
present, so there's no need to have a return value, that will also make
error path easier.

CC: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Document support for the RZ/A2 (R7S9210) SoC.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

The SDHI/MMC controller in the RZ/A2 is almost the same as R-Car gen3, but
with some minor differences.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Add imx8qxp compatible string

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-serial@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-mmc@vger.kernel.org
Cc: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

On our AT91SAM9260 board we use the same sdio bus for wifi and for the
sd card slot. This caused the atmel-mci to give the following splat on
the serial console:

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 538 at drivers/mmc/host/atmel-mci.c:859 atmci_send_command+0x24/0x44
  Modules linked in:
  CPU: 0 PID: 538 Comm: mmcqd/0 Not tainted 4.14.76 #14
  Hardware name: Atmel AT91SAM9
  [<c000fccc>] (unwind_backtrace) from [<c000d3dc>] (show_stack+0x10/0x14)
  [<c000d3dc>] (show_stack) from [<c0017644>] (__warn+0xd8/0xf4)
  [<c0017644>] (__warn) from [<c0017704>] (warn_slowpath_null+0x1c/0x24)
  [<c0017704>] (warn_slowpath_null) from [<c033bb9c>] (atmci_send_command+0x24/0x44)
  [<c033bb9c>] (atmci_send_command) from [<c033e984>] (atmci_start_request+0x1f4/0x2dc)
  [<c033e984>] (atmci_start_request) from [<c033f3b4>] (atmci_request+0xf0/0x164)
  [<c033f3b4>] (atmci_request) from [<c0327108>] (mmc_start_request+0x280/0x2d0)
  [<c0327108>] (mmc_start_request) from [<c032800c>] (mmc_start_areq+0x230/0x330)
  [<c032800c>] (mmc_start_areq) from [<c03366f8>] (mmc_blk_issue_rw_rq+0xc4/0x310)
  [<c03366f8>] (mmc_blk_issue_rw_rq) from [<c03372c4>] (mmc_blk_issue_rq+0x118/0x5ac)
  [<c03372c4>] (mmc_blk_issue_rq) from [<c033781c>] (mmc_queue_thread+0xc4/0x118)
  [<c033781c>] (mmc_queue_thread) from [<c002daf8>] (kthread+0x100/0x118)
  [<c002daf8>] (kthread) from [<c000a580>] (ret_from_fork+0x14/0x34)
  ---[ end trace 594371ddfa284bd6 ]---

This is:
  WARN_ON(host->cmd);

This was fixed on our board by letting atmci_request_end determine what
state we are in. Instead of unconditionally setting it to STATE_IDLE on
STATE_END_REQUEST.
Signed-off-by: Jonas Danielsson <jonas@orbital-systems.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

This commit removes the unnecessary of-node check since the
dw_mci_bluefield_match[] structure has only one entry.
Signed-off-by: Liming Sun <lsun@mellanox.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Merge misc fixes from Andrew Morton:
 "11 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  scripts/spdxcheck.py: always open files in binary mode
  checkstack.pl: fix for aarch64
  userfaultfd: check VM_MAYWRITE was set after verifying the uffd is registered
  fs/iomap.c: get/put the page in iomap_page_create/release()
  hugetlbfs: call VM_BUG_ON_PAGE earlier in free_huge_page()
  memblock: annotate memblock_is_reserved() with __init_memblock
  psi: fix reference to kernel commandline enable
  arch/sh/include/asm/io.h: provide prototypes for PCI I/O mapping in asm/io.h
  mm/sparse: add common helper to mark all memblocks present
  mm: introduce common STRUCT_PAGE_MAX_SHIFT define
  alpha: fix hang caused by the bootmem removal

The spdxcheck script currently falls over when confronted with a binary
file (such as Documentation/logo.gif).  To avoid that, always open files
in binary mode and decode line-by-line, ignoring encoding errors.

One tricky case is when piping data into the script and reading it from
standard input.  By default, standard input will be opened in text mode,
so we need to reopen it in binary mode.

The breakage only happens with python3 and results in a
UnicodeDecodeError (according to Uwe).

Link: http://lkml.kernel.org/r/20181212131210.28024-1-thierry.reding@gmail.com
Fixes: 6f4d29df ("scripts/spdxcheck.py: make python3 compliant")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Jeremy Cline <jcline@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joe Perches <joe@perches.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is actually a space after "sp," like this,

    ffff2000080813c8:       a9bb7bfd        stp     x29, x30, [sp, #-80]!

Right now, checkstack.pl isn't able to print anything on aarch64,
because it won't be able to match the stating objdump line of a function
due to this missing space.  Hence, it displays every stack as zero-size.

After this patch, checkpatch.pl is able to match the start of a
function's objdump, and is then able to calculate each function's stack
correctly.

Link: http://lkml.kernel.org/r/20181207195843.38528-1-cai@lca.pwSigned-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Calling UFFDIO_UNREGISTER on virtual ranges not yet registered in uffd
could trigger an harmless false positive WARN_ON.  Check the vma is
already registered before checking VM_MAYWRITE to shut off the false
positive warning.

Link: http://lkml.kernel.org/r/20181206212028.18726-2-aarcange@redhat.com
Cc: <stable@vger.kernel.org>
Fixes: 29ec9066 ("userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: syzbot+06c7092e7d71218a2c16@syzkaller.appspotmail.com
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

migrate_page_move_mapping() expects pages with private data set to have
a page_count elevated by 1.  This is what used to happen for xfs through
the buffer_heads code before the switch to iomap in commit 82cb1417
("xfs: add support for sub-pagesize writeback without buffer_heads").
Not having the count elevated causes move_pages() to fail on memory
mapped files coming from xfs.

Make iomap compatible with the migrate_page_move_mapping() assumption by
elevating the page count as part of iomap_page_create() and lowering it
in iomap_page_release().

It causes the move_pages() syscall to misbehave on memory mapped files
from xfs.  It does not not move any pages, which I suppose is "just" a
perf issue, but it also ends up returning a positive number which is out
of spec for the syscall.  Talking to Michal Hocko, it sounds like
returning positive numbers might be a necessary update to move_pages()
anyway though
(https://lkml.kernel.org/r/20181116114955.GJ14706@dhcp22.suse.cz).

I only hit this in tests that verify that move_pages() actually moved
the pages.  The test also got confused by the positive return from
move_pages() (it got treated as a success as positive numbers were not
expected and not handled) making it a bit harder to track down what's
going on.

Link: http://lkml.kernel.org/r/20181115184140.1388751-1-pjaroszynski@nvidia.com
Fixes: 82cb1417 ("xfs: add support for sub-pagesize writeback without buffer_heads")
Signed-off-by: Piotr Jaroszynski <pjaroszynski@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Brian Foster <bfoster@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>