There is no need to #define the license of the driver, just put it in
the MODULE_LICENSE() line directly as a text string.
This allows tools that check that the module license matches the source
code license to work properly, as there is no need to unwind the
unneeded dereference, especially when it is defined just a few lines
above from where it is used.
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Reported-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The initial info message (early in the xen_wdt_init_module() function)
is not very useful and we already have a message on successful probe. If
the probe fails, additional messages are printed anyway.
The version number serves no useful purpose and it ran out of favor
upstream anyway.
Signed-off-by: Radu Rendec <rrendec@arista.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Change the xen_wdt driver to use the watchdog subsystem instead of
registering and manipulating the char device directly through the misc
API. This is mainly getting rid of the "write" and "ioctl" methods and
part of the watchdog control logic (which are all implemented by the
watchdog subsystem).
Even though the watchdog subsystem supports registering and handling
multiple watchdog devices at the same time, the xen_wdt driver has an
inherent limitation of only one device due to the way the Xen hypervisor
exposes watchdog functionality. However, the driver can now coexist with
other watchdog devices (supported by different drivers).
Signed-off-by: Radu Rendec <rrendec@arista.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch adds the watchdog driver for Spreadtrum SC9860 platform.
Signed-off-by: Eric Long <eric.long@spreadtrum.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch adds the documentation for Spreadtrum watchdog driver.
Signed-off-by: Eric Long <eric.long@spreadtrum.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The watchdog core includes a worker function which pings the
watchdog until user app starts pinging it and which also
pings it if the HW require more frequent pings.
Use that function instead of the dedicated timer.
In the mean time, we can allow the user to change the timeout.
Then change the timeout module parameter to use seconds and
use the watchdog_init_timeout() core function.
On some HW (eg: the 8xx), SWCRR contains bits unrelated to the
watchdog which have to be preserved upon write.
This driver has nothing preventing the use of the magic close, so
enable it.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The first patch above (https://patchwork.kernel.org/patch/9970181/)
makes the oops go away, but it just papers over the problem. The real
problem is that the watchdog core clears WDOG_HW_RUNNING in
watchdog_stop, and the gpio driver fails to set it in its stop
function when it doesn't actually stop it. This means that the core
doesn't know that it now has responsibility for petting the device, in
turn causing the device to reset the system (I hadn't noticed this
because the board I'm working on has that reset logic disabled).
How about this (other drivers may of course have the same problem, I
haven't checked). One might say that ->stop should return an error
when the device can't be stopped, but OTOH this brings parity between
a device without a ->stop method and a GPIO wd that has always-running
set. IOW, I think ->stop should only return an error when an actual
attempt to stop the hardware failed.
From: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
The watchdog framework clears WDOG_HW_RUNNING before calling
->stop. If the driver is unable to stop the device, it is supposed to
set that bit again so that the watchdog core takes care of sending
heart-beats while the device is not open from user-space. Update the
gpio_wdt driver to honour that contract (and get rid of the redundant
clearing of WDOG_HW_RUNNING).
Fixes: 3c10bbde10 ("watchdog: core: Clear WDOG_HW_RUNNING before calling the stop function")
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Document support for the Watchdog Timer (WDT) Controller in the Renesas
R-Car V3M (r8a77970) SoC. Restore sort order while at it.
No driver update is needed.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The initial info message (early in the esb_probe() function) is not very
useful and we already have a message on successful probe, which includes
device identification. If the probe fails (e.g. PCI related errors),
additional messages are printed anyway.
The version number was only used in the initial info message. Other than
that, it serves no useful purpose and it ran out of favor upstream
anyway.
Signed-off-by: Radu Rendec <rrendec@arista.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The minimum, maximum and default values for the watchdog heartbeat
(timeout) were hardcoded in several places (including module parameter
description and warning message for invalid module parameter value).
This patch adds macros for the aforementioned values and replaces all
occurences of hardcoded values by these macros.
Signed-off-by: Radu Rendec <rrendec@arista.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Support multiple i6300esb devices simultaneously, by removing the single
device restriction in the original design and leveraging the multiple
device support of the watchdog subsystem.
This patch replaces the global definitions of watchdog device data with
a dynamically allocated structure. This structure is allocated during
device probe, so multiple independent structures can be allocated if
multiple devices are probed.
Signed-off-by: Radu Rendec <rrendec@arista.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Change the i6300esb driver to use the watchdog subsystem instead of the
legacy watchdog API. This is mainly just getting rid of the "write" and
"ioctl" methods and part of the watchdog control logic (which are all
implemented by the watchdog subsystem).
Even though the watchdog subsystem supports registering and handling
multiple watchdog devices at the same time, the i6300esb driver still
has a limitation of only one i6300esb device due to some global variable
usage that comes from the original design. However, the driver can now
coexist with other watchdog devices (supported by different drivers).
Signed-off-by: Radu Rendec <rrendec@arista.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Do not claim the NMI (i.e. return NMI_DONE) if the source of
the NMI isn't the iLO watchdog or debug.
Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The usage of of_device_get_match_data reduce the code size a bit.
Furthermore, it prevents an improbable dereference when
of_match_device() return NULL.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The Xen watchdog driver uses __kernel_time_t and ktime_to_timespec()
internally for managing its timeouts. Both are deprecated because of
y2038 problems. The driver itself is fine, since it only uses monotonic
times, but converting it to use ktime_get_seconds() avoids the deprecated
interfaces and is slightly simpler.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch removes the windows protection routine that got
now covered by the wdt core.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The DA9062 watchdog occasionally enters error condition and resets the
system if the timeout is changed quickly after the timer was enabled.
The method of disabling and waiting for > 150 µs before setting the
new timeout is taken from the DA9052 driver.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Register a restart handler for the da9062 watchdog. System restart is
triggered by sending the shutdown command to the PMIC.
As more-suitable restart handlers may exist, the priority of the
watchdog restart handler is set to 128.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The Moxart does not appear to be using the interrupt from the
watchdog timer, maybe it's not even routed, so as to support
more architectures with this driver, make the interrupt
optional.
While we are at it: actually enable the use of the interrupt
if present by setting the right bit in the control register
and define the missing control register bits.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This renames all the driver files and symbols for the Gemini
watchdog to FTWDT010 as it has been revealed that this IP block
is a generic watchdog timer from Faraday Technology used in
several SoC designs.
Select this driver by default for the Gemini, it is a sensible
driver to always have enabled.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The device tree bindings are in two copies and also should be
consolidated into a single Faraday Technology FTWDT010
binding since we uncovered that this IP part is a standard
IP from Faraday.
Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This converts the GPIO watchdog driver to use GPIO descriptors
instead of relying on the old method to read out GPIO numbers
from the device tree and then using those with the old GPIO
API.
The descriptor API keeps track of whether the line is active
low so we can remove all active low handling and rely on the
GPIO descriptor to deal with this for us.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This add "dev" and "np" variables to make the probe() function
a bit easier to read.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The only way of stopping the watchdog is by resetting it.
Add the watchdog op for stopping the device and reset if
a reset line is provided.
At same time WDOG_HW_RUNNING should be remove from dw_wdt_start.
As commented by Guenter Roeck:
dw_wdt sets WDOG_HW_RUNNING in its open function. Result is
that the kref_get() in watchdog_open() won't be executed. But then
kref_put() in close will be called since the watchdog now does stop.
This causes the imbalance.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Probing at device_initcall time lead to perverse cases where the
watchdog was probed after, say, I2C devices, which then leaves a
potentially running watchdog at the mercy of I2C device behaviour and
bus conditions.
Load the watchdog driver early to ensure that the kernel is patting it
well before initialising peripherals.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The driver also supports the watchdog in the AST25xx series, and
may work on earlier SoCs as well.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Apseed sounds like a good name for a web/mobile start-up incubator, but
isn't a reflection of Aspeed themselves.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
An unintended post-condition of probe() is that the watchdog is
disabled. This behaviour was introduced by an unnecessary write to the
control register to configure the hardware based on the devicetree. The
write is unnecessary because the cached control value that is
manipulated by the code parsing the devicetree is eventually written by
aspeed_wdt_enable(), which is when we care how the control register
should be configured.
Remove the write to restore expected behaviour.
Fixes: b7f0b8ad25 ("drivers/watchdog: ASPEED reference dev tree properties for config")
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The watchdog unit present in the JZ4780 works the same as the one in the
JZ4740.
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Add a watchdog driver for the Realtek RTD1295 SoC.
Based on QNAP's arch/arm/mach-rtk119x/driver/rtk_watchdog.c code and
mach-rtk119x/driver/dc2vo/fpga/include/iso_reg.h register defines.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Add a binding for the Realtek RTD1295 watchdog.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
memdup_user() checks it, so the only effect would be failing with
-EINVAL instead of -EFAULT in case when access_ok() is false.
However, the caller has already checked access_ok() itself (and
would have buggered off with -EFAULT), so the check is completely
pointless. Removing it both simplifies the only instance
of ->dsp_load() and allows to get rid of the check in caller -
its sole effect used to be in preventing a bogus error value
from access_ok() in the instance. Let memdup_user() do the
right thing instead...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tom Herbert says:
====================
strparser: Fix lockdep issue
When sock_owned_by_user returns true in strparser. Fix is to add and
call sock_owned_by_user_nocheck since the check for owned by user is
not an error condition in this case.
====================
Fixes: 43a0c6751a ("strparser: Stream parser for messages")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-and-tested-by: <syzbot+c91c53af67f9ebe599a337d2e70950366153b295@syzkaller.appspotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
strparser wants to check socket ownership without producing any
warnings. As indicated by the comment in the code, it is permissible
for owned_by_user to return true.
Fixes: 43a0c6751a ("strparser: Stream parser for messages")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-and-tested-by: <syzbot+c91c53af67f9ebe599a337d2e70950366153b295@syzkaller.appspotmail.com>
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows checking socket lock ownership with producing lockdep
warnings.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_copy_ubufs must unclone before it is safe to modify its
skb_shared_info with skb_zcopy_clear.
Commit b90ddd5687 ("skbuff: skb_copy_ubufs must release uarg even
without user frags") ensures that all skbs release their zerocopy
state, even those without frags.
But I forgot an edge case where such an skb arrives that is cloned.
The stack does not build such packets. Vhost/tun skbs have their
frags orphaned before cloning. TCP skbs only attach zerocopy state
when a frag is added.
But if TCP packets can be trimmed or linearized, this might occur.
Tracing the code I found no instance so far (e.g., skb_linearize
ends up calling skb_zcopy_clear if !skb->data_len).
Still, it is non-obvious that no path exists. And it is fragile to
rely on this.
Fixes: b90ddd5687 ("skbuff: skb_copy_ubufs must release uarg even without user frags")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most of the I2C headers got moved a long time ago to
include/media/i2c. Stop including them at the patch.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
d_move() will call __d_drop() and then __d_rehash()
on the dentry being moved. This creates a small window
when the dentry appears to be unhashed. Many tests
of d_unhashed() are made under ->d_lock and so are safe
from racing with this window, but some aren't.
In particular, getcwd() calls d_unlinked() (which calls
d_unhashed()) without d_lock protection, so it can race.
This races has been seen in practice with lustre, which uses d_move() as
part of name lookup. See:
https://jira.hpdd.intel.com/browse/LU-9735
It could race with a regular rename(), and result in ENOENT instead
of either the 'before' or 'after' name.
The race can be demonstrated with a simple program which
has two threads, one renaming a directory back and forth
while another calls getcwd() within that directory: it should never
fail, but does. See:
https://patchwork.kernel.org/patch/9455345/
We could fix this race by taking d_lock and rechecking when
d_unhashed() reports true. Alternately when can remove the window,
which is the approach this patch takes.
___d_drop() is introduce which does *not* clear d_hash.pprev
so the dentry still appears to be hashed. __d_drop() calls
___d_drop(), then clears d_hash.pprev.
__d_move() now uses ___d_drop() and only clears d_hash.pprev
when not rehashing.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
