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The ->reset_slot callback introduced by commits:
2e35afaefe64 ("PCI: pciehp: Add reset_slot() method") and
06a8d89af551 ("PCI: pciehp: Disable link notification across slot reset")
disables notification of Presence Detect Changed and Data Link Layer
State Changed events for the duration of a secondary bus reset.
However a bus reset not only triggers these events, but may also clear
the Presence Detect State bit in the Slot Status register and the Data
Link Layer Link Active bit in the Link Status register momentarily.
According to Sinan Kaya:
"I know for a fact that bus reset clears the Data Link Layer Active bit
as soon as link goes down. It gets set again following link up.
Presence detect depends on the HW implementation. QDT root ports
don't change presence detect for instance since nobody actually
removed the card. If an implementation supports in-band presence
detect, the answer is yes. As soon as the link goes down, presence
detect bit will get cleared until recovery."
https://lkml.kernel.org/r/[email protected]
In-band presence detect is also covered in Table 4-15 in PCIe r4.0,
sec 4.2.6.
pciehp should therefore ensure that any parts of the driver that access
those bits do not run concurrently to a bus reset. The only precaution
the commits took to that effect was to halt interrupt polling. They
made no effort to drain the slot workqueue, cancel an outstanding
Attention Button work, or block slot enable/disable requests via sysfs
and in the ->probe hook.
Now that pciehp is converted to enable/disable the slot exclusively from
the IRQ thread, the only places accessing the two above-mentioned bits
are the IRQ thread and the ->probe hook. Add locking to serialize them
with a bus reset. This obviates the need to halt interrupt polling.
Do not add locking to the ->get_adapter_status sysfs callback to afford
users unfettered access to that bit. Use an rw_semaphore in lieu of a
regular mutex to allow parallel execution of the non-reset code paths
accessing the critical bits, i.e. the IRQ thread and the ->probe hook.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Rajat Jain <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Sinan Kaya <[email protected]>
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Per PCIe r4.0, sec 6.7.3.4, a "port may optionally send an MSI when
there are hot-plug events that occur while interrupt generation is
disabled, and interrupt generation is subsequently enabled."
On probe, we currently clear all event bits in the Slot Status register
with the notable exception of the Presence Detect Changed bit. Thereby
we seek to receive an interrupt for an already occupied slot once event
notification is enabled.
But because the interrupt is optional, users may have to specify the
pciehp_force parameter on the command line, which is inconvenient.
Moreover, now that pciehp's event handling has become resilient to
missed events, a Presence Detect Changed interrupt for a slot which is
powered on is interpreted as removal of the card. If the slot has
already been brought up by the BIOS, receiving such an interrupt on
probe causes the slot to be powered off and immediately back on, which
is likewise undesirable.
Avoid both issues by making the behavior of pciehp_force the default and
clearing the Presence Detect Changed bit on probe.
Note that the stated purpose of pciehp_force per the MODULE_PARM_DESC
("Force pciehp, even if OSHP is missing") seems nonsensical because the
OSHP control method is only relevant for SHCP slots according to the
PCI Firmware specification r3.0, sec 4.8.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Mika Westerberg <[email protected]>
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A hotplug port's Slot Status register does not count how often each type
of event occurred, it only records the fact *that* an event has occurred.
Previously pciehp queued a work item for each event. But if it missed
an event, e.g. removal of a card in-between two back-to-back insertions,
it queued up the wrong work item or no work item at all. Commit
fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking
for new ones") sought to improve the situation by shrinking the window
during which events may be missed.
But Stefan Roese reports unbalanced Card present and Link Up events,
suggesting that we're still missing events if they occur very rapidly.
Bjorn Helgaas responds that he considers pciehp's event handling
"baroque" and calls for its simplification and rationalization:
https://lkml.kernel.org/r/[email protected]
It gets worse once a hotplug port is runtime suspended: The port can
signal an interrupt while it and its parents are in D3hot, i.e. while
it is inaccessible. By the time we've runtime resumed all parents to D0
and read the port's Slot Status register, we may have missed an arbitrary
number of events. Event handling therefore needs to be reworked to
become resilient to missed events.
Assume that a Presence Detect Changed event has occurred.
Consider the following truth table:
- Slot is in OFF_STATE and is currently empty. => Do nothing.
(The event is trailing a Link Down or we've
missed an insertion and subsequent removal.)
- Slot is in OFF_STATE and is currently occupied. => Turn the slot on.
- Slot is in ON_STATE and is currently empty. => Turn the slot off.
- Slot is in ON_STATE and is currently occupied. => Turn the slot off,
(Be cautious and assume the card in then back on.
the slot isn't the same as before.)
This leads to the following simple algorithm:
1 If the slot is in ON_STATE, turn it off unconditionally.
2 If the slot is currently occupied, turn it on.
Because those actions are now carried out synchronously, rather than by
scheduled work items, pciehp reacts to the *current* situation and
missed events no longer matter.
Data Link Layer State Changed events can be handled identically to
Presence Detect Changed events. Note that in the above truth table,
a Link Up trailing a Card present event didn't have to be accounted for:
It is filtered out by pciehp_check_link_status().
As for Attention Button Pressed events, PCIe r4.0, sec 6.7.1.5 says:
"Once the Power Indicator begins blinking, a 5-second abort interval
exists during which a second depression of the Attention Button cancels
the operation." In other words, the user can only expect the system to
react to a button press after it starts blinking. Missed button presses
that occur in-between are irrelevant.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Mayurkumar Patel <[email protected]>
Cc: Mika Westerberg <[email protected]>
Cc: Kenji Kaneshige <[email protected]>
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When a device is hotplugged, Presence Detect and Link Up events often do
not occur simultaneously, but with a lag of a few milliseconds. Only
the first event received is relevant, the other one can be disregarded.
Moreover, Stefan Roese reports that on certain platforms, Link State and
Presence Detect may flap for up to 100 ms before stabilizing, suggesting
that such events should be disregarded for at least this long:
https://lkml.kernel.org/r/[email protected]
On slot enablement, pciehp_check_link_status() waits for 100 ms per
PCIe r4.0, sec 6.7.3.3, then probes the hotplugged device's vendor
register for up to 1 second.
If this succeeds, the link is definitely up, so ignore any Presence
Detect or Link State events that occurred up to this point.
pciehp_check_link_status() then checks the Link Training bit in the
Link Status register. This is the final opportunity to detect
inaccessibility of the device and abort slot enablement. Any link
or presence change that occurs afterwards will cause the slot to be
disabled again immediately after attempting to enable it.
The astute reviewer may appreciate that achieving this behavior would be
more complicated had pciehp not just been converted to enable/disable
the slot exclusively from the IRQ thread: When the slot is enabled via
sysfs, each link or presence flap would otherwise cause the IRQ thread
to run and it would have to sense that those events are belonging to a
concurrent slot enablement operation and disregard them. It would be
much more difficult than this mere 3 line change.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Stefan Roese <[email protected]>
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No callers of pciehp_enable/disable_slot() outside of pciehp_ctrl.c
remain, so declare the functions static. For now this requires forward
declarations. Those can be eliminated by reshuffling functions once the
ongoing effort to refactor the driver has settled.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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Previously slot enablement and disablement could happen concurrently.
But now it's under the exclusive control of the IRQ thread, rendering
the locking obsolete. Drop it.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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Besides the IRQ thread, there are several other places in the driver
which enable or disable the slot:
- pciehp_probe() enables the slot if it's occupied and the pciehp_force
module parameter is used.
- pciehp_resume() enables or disables the slot after system sleep.
- pciehp_queue_pushbutton_work() enables or disables the slot after the
5 second delay following an Attention Button press.
- pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or
disable the slot on sysfs write.
This requires locking and complicates pciehp's state machine.
A simplification can be achieved by enabling and disabling the slot
exclusively from the IRQ thread.
Amend the functions listed above to request slot enable/disablement from
the IRQ thread by either synthesizing a Presence Detect Changed event or,
in the case of a disable user request (via sysfs or an Attention Button
press), submitting a newly introduced force disable request. The latter
is needed because the slot shall be forced off despite being occupied.
For this force disable request, avoid colliding with Slot Status register
bits by using a bit number greater than 16.
For synchronous execution of requests (on sysfs write), wait for the
request to finish and retrieve the result. There can only ever be one
sysfs write in flight due to the locking in kernfs_fop_write(), hence
there is no risk of returning the result of a different sysfs request to
user space.
The POWERON_STATE and POWEROFF_STATE is now no longer entered by the
above-listed functions, but solely by the IRQ thread when it begins a
power transition. Afterwards, it moves to STATIC_STATE. The same
applies to canceling the Attention Button work, it likewise becomes an
IRQ thread only operation.
An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is
never observed by the IRQ thread itself, only by functions called in a
different context, such as pciehp_sysfs_enable_slot(). So remove
handling of these states from pciehp_handle_button_press() and
pciehp_handle_link_change() which are exclusively called from the IRQ
thread.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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handle_button_press_event() currently determines whether the slot has
been turned on or off by looking at the Power Controller Control bit in
the Slot Control register. This assumes that an attention button
implies presence of a power controller even though that's not mandated
by the spec. Moreover the Power Controller Control bit is unreliable
when a power fault occurs (PCIe r4.0, sec 6.7.1.8). This issue has
existed since the driver was introduced in 2004.
Fix by replacing STATIC_STATE with ON_STATE and OFF_STATE and tracking
whether the slot has been turned on or off. This is also a required
ingredient to make pciehp resilient to missed events, which is the
object of an upcoming commit.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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The PCI hotplug core has just been refactored to separate slot
initialization for in-kernel use from publication to user space.
Take advantage of it in pciehp by publishing to user space last on
probe. This will allow enable/disablement of the slot exclusively from
the IRQ thread because the IRQ is requested after initialization for
in-kernel use (thereby getting its unique name needed by the IRQ thread)
but before user space is able to submit enable/disable requests.
On teardown, the order is the same in reverse: The user space interface
is removed prior to freeing the IRQ and destroying the slot.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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When a hotplug driver calls pci_hp_register(), all steps necessary for
registration are carried out in one go, including creation of a kobject
and addition to sysfs. That's a problem for pciehp once it's converted
to enable/disable the slot exclusively from the IRQ thread: The thread
needs to be spawned after creation of the kobject (because it uses the
kobject's name), but before addition to sysfs (because it will handle
enable/disable requests submitted via sysfs).
pci_hp_deregister() does offer a ->release callback that's invoked
after deletion from sysfs and before destruction of the kobject. But
because pci_hp_register() doesn't offer a counterpart, hotplug drivers'
->probe and ->remove code becomes asymmetric, which is error prone
as recently discovered use-after-free bugs in pciehp's ->remove hook
have shown.
In a sense, this appears to be a case of the midlayer antipattern:
"The core thesis of the "midlayer mistake" is that midlayers are
bad and should not exist. That common functionality which it is
so tempting to put in a midlayer should instead be provided as
library routines which can [be] used, augmented, or ignored by
each bottom level driver independently. Thus every subsystem
that supports multiple implementations (or drivers) should
provide a very thin top layer which calls directly into the
bottom layer drivers, and a rich library of support code that
eases the implementation of those drivers. This library is
available to, but not forced upon, those drivers."
-- Neil Brown (2009), https://lwn.net/Articles/336262/
The presence of midlayer traits in the PCI hotplug core might be ascribed
to its age: When it was introduced in February 2002, the blessings of a
library approach might not have been well known:
https://git.kernel.org/tglx/history/c/a8a2069f432c
For comparison, the driver core does offer split functions for creating
a kobject (device_initialize()) and addition to sysfs (device_add()) as
an alternative to carrying out everything at once (device_register()).
This was introduced in October 2002:
https://git.kernel.org/tglx/history/c/8b290eb19962
The odd ->release callback in the PCI hotplug core was added in 2003:
https://git.kernel.org/tglx/history/c/69f8d663b595
Clearly, a library approach would not force every hotplug driver to
implement a ->release callback, but rather allow the driver to remove
the sysfs files, release its data structures and finally destroy the
kobject. Alternatively, a driver may choose to remove everything with
pci_hp_deregister(), then release its data structures.
To this end, offer drivers pci_hp_initialize() and pci_hp_add() as a
split-up version of pci_hp_register(). Likewise, offer pci_hp_del()
and pci_hp_destroy() as a split-up version of pci_hp_deregister().
Eliminate the ->release callback and move its code into each driver's
teardown routine.
Declare pci_hp_deregister() void, in keeping with the usual kernel
pattern that enablement can fail, but disablement cannot. It only
returned an error if the caller passed in a NULL pointer or a slot which
has never or is no longer registered or is sharing its name with another
slot. Those would be bugs, so WARN about them. Few hotplug drivers
actually checked the return value and those that did only printed a
useless error message to dmesg. Remove that.
For most drivers the conversion was straightforward since it doesn't
matter whether the code in the ->release callback is executed before or
after destruction of the kobject. But in the case of ibmphp, it was
unclear to me whether setting slot_cur->ctrl and slot_cur->bus_on to
NULL needs to happen before the kobject is destroyed, so I erred on
the side of caution and ensured that the order stays the same. Another
nontrivial case is pnv_php, I've found the list and kref logic difficult
to understand, however my impression was that it is safe to delete the
list element and drop the references until after the kobject is
destroyed.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Andy Shevchenko <[email protected]> # drivers/platform/x86
Cc: Rafael J. Wysocki <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Scott Murray <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Gavin Shan <[email protected]>
Cc: Sebastian Ott <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: Corentin Chary <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Andy Shevchenko <[email protected]>
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Previously the slot workqueue was used to handle events and enable or
disable the slot. That's no longer the case as those tasks are done
synchronously in the IRQ thread. The slot workqueue is thus merely used
to handle a button press after the 5 second delay and only one such work
item may be in flight at any given time. A separate workqueue isn't
necessary for this simple task, so use the system workqueue instead.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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Up until now, pciehp's IRQ handler schedules a work item for each event,
which in turn schedules a work item to enable or disable the slot. This
double indirection was necessary because sleeping wasn't allowed in the
IRQ handler.
However it is now that pciehp has been converted to threaded IRQ handling
and polling, so handle events synchronously in pciehp_ist() and remove
the work item infrastructure (with the exception of work items to handle
a button press after the 5 second delay).
For link or presence change events, move the register read to determine
the current link or presence state behind acquisition of the slot lock
to prevent it from becoming stale while the lock is contended.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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If the attention button is pressed to power on the slot AND the user
powers on the slot via sysfs before 5 seconds have elapsed AND powering
on the slot fails because either the slot is unoccupied OR the latch is
open, we neglect turning off the green LED so it keeps on blinking.
That's because the error path of pciehp_sysfs_enable_slot() doesn't call
pciehp_green_led_off(), unlike pciehp_power_thread() which does.
The bug has been present since 2004 when the driver was introduced.
Fix by deduplicating common code in pciehp_sysfs_enable_slot() and
pciehp_power_thread() into a wrapper function pciehp_enable_slot() and
renaming the existing function to __pciehp_enable_slot(). Same for
pciehp_disable_slot(). This will also simplify the upcoming rework of
pciehp's event handling.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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We've just converted pciehp to threaded IRQ handling, but still cannot
sleep in pciehp_ist() because the function is also called in poll mode,
which runs in softirq context (from a timer).
Convert poll mode to a kthread so that pciehp_ist() always runs in task
context.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Thomas Gleixner <[email protected]>
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pciehp's IRQ handler queues up a work item for each event signaled by
the hardware. A more modern alternative is to let a long running
kthread service the events. The IRQ handler's sole job is then to check
whether the IRQ originated from the device in question, acknowledge its
receipt to the hardware to quiesce the interrupt and wake up the kthread.
One benefit is reduced latency to handle the IRQ, which is a necessity
for realtime environments. Another benefit is that we can make pciehp
simpler and more robust by handling events synchronously in process
context, rather than asynchronously by queueing up work items. pciehp's
usage of work items is a historic artifact, it predates the introduction
of threaded IRQ handlers by two years. (The former was introduced in
2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the
latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt
handler support").)
Convert pciehp to threaded IRQ handling by retrieving the pending events
in pciehp_isr(), saving them for later consumption by the thread handler
pciehp_ist() and clearing them in the Slot Status register.
By clearing the Slot Status (and thereby acknowledging the events) in
pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which
would have the unpleasant side effect of starving devices sharing the
IRQ until pciehp_ist() has finished.
pciehp_isr() does not count how many times each event occurred, but
merely records the fact *that* an event occurred. If the same event
occurs a second time before pciehp_ist() is woken, that second event
will not be recorded separately, which is problematic according to
commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before
looking for new ones") because we may miss removal of a card in-between
two back-to-back insertions. We're about to make pciehp_ist() resilient
to missed events. The present commit regresses the driver's behavior
temporarily in order to separate the changes into reviewable chunks.
This doesn't affect regular slow-motion hotplug, only plug-unplug-plug
operations that happen in a timespan shorter than wakeup of the IRQ
thread.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Mayurkumar Patel <[email protected]>
Cc: Kenji Kaneshige <[email protected]>
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Document the driver's data structures to lower the barrier to entry for
contributors.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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Since commit 0f4bd8014db5 ("PCI: hotplug: Drop checking of PCI_BRIDGE_
CONTROL in *_unconfigure_device()"), pciehp_unconfigure_device() can no
longer fail, so declare it and its sole caller remove_board() void, in
keeping with the usual kernel pattern that enablement can fail, but
disablement cannot. No functional change intended.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Mika Westerberg <[email protected]>
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pciehp_disable_slot() checks if the ctrl attribute of the slot is NULL
and bails out if so. However the function is not called prior to the
attribute being set in pcie_init_slot(), and pcie_init_slot() is not
called if ctrl is NULL. So the check is unnecessary. Drop it.
It has been present ever since the driver was introduced in 2004, but it
was already unnecessary back then:
https://git.kernel.org/tglx/history/c/c16b4b14d980
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
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Commit b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug
events for a device") iterates over the devices on a hotplug port's
subordinate bus in pciehp's IRQ handler without acquiring pci_bus_sem.
It is thus possible for a user to cause a crash by concurrently
manipulating the device list, e.g. by disabling slot power via sysfs
on a different CPU or by initiating a remove/rescan via sysfs.
This can't be fixed by acquiring pci_bus_sem because it may sleep.
The simplest fix is to avoid the list iteration altogether and just
check the ignore_hotplug flag on the port itself. This works because
pci_ignore_hotplug() sets the flag both on the device as well as on its
parent bridge.
We do lose the ability to print the name of the device blocking hotplug
in the debug message, but that's probably bearable.
Fixes: b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device")
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: [email protected]
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When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the
hotplug_slot struct is deregistered and thus freed before freeing the
IRQ. The IRQ handler and the work items it schedules print the slot
name referenced from the freed structure in various informational and
debug log messages, each time resulting in a quadruple dereference of
freed pointers (hotplug_slot -> pci_slot -> kobject -> name).
At best the slot name is logged as "(null)", at worst kernel memory is
exposed in logs or the driver crashes:
pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present
An attacker may provoke the bug by unplugging multiple devices on a
Thunderbolt daisy chain at once. Unplugging can also be simulated by
powering down slots via sysfs. The bug is particularly easy to trigger
in poll mode.
It has been present since the driver's introduction in 2004:
https://git.kernel.org/tglx/history/c/c16b4b14d980
Fix by rearranging teardown such that the IRQ is freed first. Run the
work items queued by the IRQ handler to completion before freeing the
hotplug_slot struct by draining the work queue from the ->release_slot
callback which is invoked by pci_hp_deregister().
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: [email protected] # v2.6.4
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If addition of sysfs files fails on registration of a hotplug slot, the
struct pci_slot as well as the entry in the slot_list is leaked. The
issue has been present since the hotplug core was introduced in 2002:
https://git.kernel.org/tglx/history/c/a8a2069f432c
Perhaps the idea was that even though sysfs addition fails, the slot
should still be usable. But that's not how drivers use the interface,
they abort probe if a non-zero value is returned.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: [email protected] # v2.4.15+
Cc: Greg Kroah-Hartman <[email protected]>
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Ten years ago, commit 58319b802a61 ("PCI: Hotplug core: remove 'name'")
dropped the name element from struct hotplug_slot but neglected to update
the skeleton driver.
That same year, commit f46753c5e354 ("PCI: introduce pci_slot") raised the
number of arguments to pci_hp_register() from one to four.
Fourteen years ago, historic commit 7ab60fc1b8e7 ("PCI Hotplug skeleton:
final cleanups") removed all usages of the retval variable from
pcihp_skel_init() but not the variable itself, provoking a compiler
warning: https://git.kernel.org/tglx/history/c/7ab60fc1b8e7
It seems fair to assume the driver hasn't been used as a template for a new
driver in a while. Per Bjorn's and Christoph's preference, delete it.
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Christoph Hellwig <[email protected]>
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The shpchp driver registers for all PCI bridge devices. Its probe method
should fail if either (1) the bridge doesn't have an SHPC or (2) the OS
isn't allowed to use it (the platform firmware may be operating the SHPC
itself).
Separate these two tests into:
- A new shpc_capable() that looks for the SHPC hardware and is applicable
on all systems (ACPI and non-ACPI), and
- A simplified acpi_get_hp_hw_control_from_firmware() that we call only
when we already know an SHPC exists and there may be ACPI methods to
either request permission to use it (_OSC) or transfer control to the
OS (OSHP).
acpi_get_hp_hw_control_from_firmware() is implemented when CONFIG_ACPI=y,
but does nothing if the current platform doesn't support ACPI.
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Mika Westerberg <[email protected]>
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An SHPC can be operated either by platform firmware or by the OS. The OS
uses a host bridge ACPI _OSC method to negotiate for control of SHPC. If
firmware wants to prevent an OS from operating an SHPC, it must supply an
_OSC method that declines to grant SHPC ownership to the OS.
If acpi_pci_find_root() returns NULL, it means there's no ACPI host bridge
device (PNP0A03 or PNP0A08) and hence no _OSC method, so the OS is always
allowed to manage the SHPC.
Fix a NULL pointer dereference when CONFIG_ACPI=y but the current
hardware/firmware platform doesn't support ACPI. In that case,
acpi_get_hp_hw_control_from_firmware() is implemented but
acpi_pci_find_root() returns NULL.
Fixes: 90cc0c3cc709 ("PCI: shpchp: Add shpchp_is_native()")
Link: https://lkml.kernel.org/r/[email protected]
Reported-by: Marc Zyngier <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Mika Westerberg <[email protected]>
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Pull block fixes from Jens Axboe:
"A collection of fixes that should go into -rc1. This contains:
- bsg_open vs bsg_unregister race fix (Anatoliy)
- NVMe pull request from Christoph, with fixes for regressions in
this window, FC connect/reconnect path code unification, and a
trace point addition.
- timeout fix (Christoph)
- remove a few unused functions (Christoph)
- blk-mq tag_set reinit fix (Roman)"
* tag 'for-linus-20180616' of git://git.kernel.dk/linux-block:
bsg: fix race of bsg_open and bsg_unregister
block: remov blk_queue_invalidate_tags
nvme-fabrics: fix and refine state checks in __nvmf_check_ready
nvme-fabrics: handle the admin-only case properly in nvmf_check_ready
nvme-fabrics: refactor queue ready check
blk-mq: remove blk_mq_tagset_iter
nvme: remove nvme_reinit_tagset
nvme-fc: fix nulling of queue data on reconnect
nvme-fc: remove reinit_request routine
blk-mq: don't time out requests again that are in the timeout handler
nvme-fc: change controllers first connect to use reconnect path
nvme: don't rely on the changed namespace list log
nvmet: free smart-log buffer after use
nvme-rdma: fix error flow during mapping request data
nvme: add bio remapping tracepoint
nvme: fix NULL pointer dereference in nvme_init_subsystem
blk-mq: reinit q->tag_set_list entry only after grace period
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Pull documentation fixes from Mauro Carvalho Chehab:
"This solves a series of broken links for files under Documentation,
and improves a script meant to detect such broken links (see
scripts/documentation-file-ref-check).
The changes on this series are:
- can.rst: fix a footnote reference;
- crypto_engine.rst: Fix two parsing warnings;
- Fix a lot of broken references to Documentation/*;
- improve the scripts/documentation-file-ref-check script, in order
to help detecting/fixing broken references, preventing
false-positives.
After this patch series, only 33 broken references to doc files are
detected by scripts/documentation-file-ref-check"
* tag 'docs-broken-links' of git://linuxtv.org/mchehab/experimental: (26 commits)
fix a series of Documentation/ broken file name references
Documentation: rstFlatTable.py: fix a broken reference
ABI: sysfs-devices-system-cpu: remove a broken reference
devicetree: fix a series of wrong file references
devicetree: fix name of pinctrl-bindings.txt
devicetree: fix some bindings file names
MAINTAINERS: fix location of DT npcm files
MAINTAINERS: fix location of some display DT bindings
kernel-parameters.txt: fix pointers to sound parameters
bindings: nvmem/zii: Fix location of nvmem.txt
docs: Fix more broken references
scripts/documentation-file-ref-check: check tools/*/Documentation
scripts/documentation-file-ref-check: get rid of false-positives
scripts/documentation-file-ref-check: hint: dash or underline
scripts/documentation-file-ref-check: add a fix logic for DT
scripts/documentation-file-ref-check: accept more wildcards at filenames
scripts/documentation-file-ref-check: fix help message
media: max2175: fix location of driver's companion documentation
media: v4l: fix broken video4linux docs locations
media: dvb: point to the location of the old README.dvb-usb file
...
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
"fsnotify cleanups unifying handling of different watch types.
This is the shortened fsnotify series from Amir with the last five
patches pulled out. Amir has modified those patches to not change
struct inode but obviously it's too late for those to go into this
merge window"
* tag 'fsnotify_for_v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fsnotify: add fsnotify_add_inode_mark() wrappers
fanotify: generalize fanotify_should_send_event()
fsnotify: generalize send_to_group()
fsnotify: generalize iteration of marks by object type
fsnotify: introduce marks iteration helpers
fsnotify: remove redundant arguments to handle_event()
fsnotify: use type id to identify connector object type
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Pull fbdev updates from Bartlomiej Zolnierkiewicz:
"There is nothing really major here, few small fixes, some cleanups and
dead drivers removal:
- mark omapfb drivers as orphans in MAINTAINERS file (Tomi Valkeinen)
- add missing module license tags to omap/omapfb driver (Arnd
Bergmann)
- add missing GPIOLIB dependendy to omap2/omapfb driver (Arnd
Bergmann)
- convert savagefb, aty128fb & radeonfb drivers to use msleep & co.
(Jia-Ju Bai)
- allow COMPILE_TEST build for viafb driver (media part was reviewed
by media subsystem Maintainer)
- remove unused MERAM support from sh_mobile_lcdcfb and shmob-drm
drivers (drm parts were acked by shmob-drm driver Maintainer)
- remove unused auo_k190xfb drivers
- misc cleanups (Souptick Joarder, Wolfram Sang, Markus Elfring, Andy
Shevchenko, Colin Ian King)"
* tag 'fbdev-v4.18' of git://github.com/bzolnier/linux: (26 commits)
fb_omap2: add gpiolib dependency
video/omap: add module license tags
MAINTAINERS: make omapfb orphan
video: fbdev: pxafb: match_string() conversion fixup
video: fbdev: nvidia: fix spelling mistake: "scaleing" -> "scaling"
video: fbdev: fix spelling mistake: "frambuffer" -> "framebuffer"
video: fbdev: pxafb: Convert to use match_string() helper
video: fbdev: via: allow COMPILE_TEST build
video: fbdev: remove unused sh_mobile_meram driver
drm: shmobile: remove unused MERAM support
video: fbdev: sh_mobile_lcdcfb: remove unused MERAM support
video: fbdev: remove unused auo_k190xfb drivers
video: omap: Improve a size determination in omapfb_do_probe()
video: sm501fb: Improve a size determination in sm501fb_probe()
video: fbdev-MMP: Improve a size determination in path_init()
video: fbdev-MMP: Delete an error message for a failed memory allocation in two functions
video: auo_k190x: Delete an error message for a failed memory allocation in auok190x_common_probe()
video: sh_mobile_lcdcfb: Delete an error message for a failed memory allocation in two functions
video: sh_mobile_meram: Delete an error message for a failed memory allocation in sh_mobile_meram_probe()
video: fbdev: sh_mobile_meram: Drop SUPERH platform dependency
...
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull AFS updates from Al Viro:
"Assorted AFS stuff - ended up in vfs.git since most of that consists
of David's AFS-related followups to Christoph's procfs series"
* 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
afs: Optimise callback breaking by not repeating volume lookup
afs: Display manually added cells in dynamic root mount
afs: Enable IPv6 DNS lookups
afs: Show all of a server's addresses in /proc/fs/afs/servers
afs: Handle CONFIG_PROC_FS=n
proc: Make inline name size calculation automatic
afs: Implement network namespacing
afs: Mark afs_net::ws_cell as __rcu and set using rcu functions
afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus()
proc: Add a way to make network proc files writable
afs: Rearrange fs/afs/proc.c to remove remaining predeclarations.
afs: Rearrange fs/afs/proc.c to move the show routines up
afs: Rearrange fs/afs/proc.c by moving fops and open functions down
afs: Move /proc management functions to the end of the file
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat updates from Al Viro:
"Some biarch patches - getting rid of assorted (mis)uses of
compat_alloc_user_space().
Not much in that area this cycle..."
* 'work.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
orangefs: simplify compat ioctl handling
signalfd: lift sigmask copyin and size checks to callers of do_signalfd4()
vmsplice(): lift importing iovec into vmsplice(2) and compat counterpart
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull aio fixes from Al Viro:
"Assorted AIO followups and fixes"
* 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
eventpoll: switch to ->poll_mask
aio: only return events requested in poll_mask() for IOCB_CMD_POLL
eventfd: only return events requested in poll_mask()
aio: mark __aio_sigset::sigmask const
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Pull networking fixes from David Miller:
1) Various netfilter fixlets from Pablo and the netfilter team.
2) Fix regression in IPVS caused by lack of PMTU exceptions on local
routes in ipv6, from Julian Anastasov.
3) Check pskb_trim_rcsum for failure in DSA, from Zhouyang Jia.
4) Don't crash on poll in TLS, from Daniel Borkmann.
5) Revert SO_REUSE{ADDR,PORT} change, it regresses various things
including Avahi mDNS. From Bart Van Assche.
6) Missing of_node_put in qcom/emac driver, from Yue Haibing.
7) We lack checking of the TCP checking in one special case during SYN
receive, from Frank van der Linden.
8) Fix module init error paths of mac80211 hwsim, from Johannes Berg.
9) Handle 802.1ad properly in stmmac driver, from Elad Nachman.
10) Must grab HW caps before doing quirk checks in stmmac driver, from
Jose Abreu.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (81 commits)
net: stmmac: Run HWIF Quirks after getting HW caps
neighbour: skip NTF_EXT_LEARNED entries during forced gc
net: cxgb3: add error handling for sysfs_create_group
tls: fix waitall behavior in tls_sw_recvmsg
tls: fix use-after-free in tls_push_record
l2tp: filter out non-PPP sessions in pppol2tp_tunnel_ioctl()
l2tp: reject creation of non-PPP sessions on L2TPv2 tunnels
mlxsw: spectrum_switchdev: Fix port_vlan refcounting
mlxsw: spectrum_router: Align with new route replace logic
mlxsw: spectrum_router: Allow appending to dev-only routes
ipv6: Only emit append events for appended routes
stmmac: added support for 802.1ad vlan stripping
cfg80211: fix rcu in cfg80211_unregister_wdev
mac80211: Move up init of TXQs
mac80211_hwsim: fix module init error paths
cfg80211: initialize sinfo in cfg80211_get_station
nl80211: fix some kernel doc tag mistakes
hv_netvsc: Fix the variable sizes in ipsecv2 and rsc offload
rds: avoid unenecessary cong_update in loop transport
l2tp: clean up stale tunnel or session in pppol2tp_connect's error path
...
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git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull module updates from Jessica Yu:
"Minor code cleanup and also allow sig_enforce param to be shown in
sysfs with CONFIG_MODULE_SIG_FORCE"
* tag 'modules-for-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Allow to always show the status of modsign
module: Do not access sig_enforce directly
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git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml
Pull uml updates from Richard Weinberger:
"Minor updates for UML:
- fixes for our new vector network driver by Anton
- initcall cleanup by Alexander
- We have a new mailinglist, sourceforge.net sucks"
* 'for-linus-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Fix raw interface options
um: Fix initialization of vector queues
um: remove uml initcalls
um: Update mailing list address
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git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux
Pull RISC-V updates from Palmer Dabbelt:
"This contains some small RISC-V updates I'd like to target for 4.18.
They are all fairly small this time. Here's a short summary, there's
more info in the commits/merges:
- a fix to __clear_user to respect the passed arguments.
- enough support for the perf subsystem to work with RISC-V's ISA
defined performance counters.
- support for sparse and cleanups suggested by it.
- support for R_RISCV_32 (a relocation, not the 32-bit ISA).
- some MAINTAINERS cleanups.
- the addition of CONFIG_HVC_RISCV_SBI to our defconfig, as it's
always present.
I've given these a simple build+boot test"
* tag 'riscv-for-linus-4.18-merge_window' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
RISC-V: Add CONFIG_HVC_RISCV_SBI=y to defconfig
RISC-V: Handle R_RISCV_32 in modules
riscv/ftrace: Export _mcount when DYNAMIC_FTRACE isn't set
riscv: add riscv-specific predefines to CHECKFLAGS
riscv: split the declaration of __copy_user
riscv: no __user for probe_kernel_address()
riscv: use NULL instead of a plain 0
perf: riscv: Add Document for Future Porting Guide
perf: riscv: preliminary RISC-V support
MAINTAINERS: Update Albert's email, he's back at Berkeley
MAINTAINERS: Add myself as a maintainer for SiFive's drivers
riscv: Fix the bug in memory access fixup code
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Pull more kvm updates from Paolo Bonzini:
"Mostly the PPC part of the release, but also switching to Arnd's fix
for the hyperv config issue and a typo fix.
Main PPC changes:
- reimplement the MMIO instruction emulation
- transactional memory support for PR KVM
- improve radix page table handling"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (63 commits)
KVM: x86: VMX: redo fix for link error without CONFIG_HYPERV
KVM: x86: fix typo at kvm_arch_hardware_setup comment
KVM: PPC: Book3S PR: Fix failure status setting in tabort. emulation
KVM: PPC: Book3S PR: Enable use on POWER9 bare-metal hosts in HPT mode
KVM: PPC: Book3S PR: Don't let PAPR guest set MSR hypervisor bit
KVM: PPC: Book3S PR: Fix failure status setting in treclaim. emulation
KVM: PPC: Book3S PR: Fix MSR setting when delivering interrupts
KVM: PPC: Book3S PR: Handle additional interrupt types
KVM: PPC: Book3S PR: Enable kvmppc_get/set_one_reg_pr() for HTM registers
KVM: PPC: Book3S: Remove load/put vcpu for KVM_GET_REGS/KVM_SET_REGS
KVM: PPC: Remove load/put vcpu for KVM_GET/SET_ONE_REG ioctl
KVM: PPC: Move vcpu_load/vcpu_put down to each ioctl case in kvm_arch_vcpu_ioctl
KVM: PPC: Book3S PR: Enable HTM for PR KVM for KVM_CHECK_EXTENSION ioctl
KVM: PPC: Book3S PR: Support TAR handling for PR KVM HTM
KVM: PPC: Book3S PR: Add guard code to prevent returning to guest with PR=0 and Transactional state
KVM: PPC: Book3S PR: Add emulation for tabort. in privileged state
KVM: PPC: Book3S PR: Add emulation for trechkpt.
KVM: PPC: Book3S PR: Add emulation for treclaim.
KVM: PPC: Book3S PR: Restore NV regs after emulating mfspr from TM SPRs
KVM: PPC: Book3S PR: Always fail transactions in guest privileged state
...
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Pull virtio updates from Michael Tsirkin:
"virtio, vhost: features, fixes
- PCI virtual function support for virtio
- DMA barriers for virtio strong barriers
- bugfixes"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio: update the comments for transport features
virtio_pci: support enabling VFs
vhost: fix info leak due to uninitialized memory
virtio_ring: switch to dma_XX barriers for rpmsg
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As files move around, their previous links break. Fix the
references for them.
Acked-by: Andy Shevchenko <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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The old HOWTO was removed a long time ago. The flat table
version is not metioned elsewhere, so just get rid of the
text.
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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This file doesn't exist anymore:
Documentation/cpu-freq/user-guide.txt
As the ABI already points to Documentation/cpu-freq, just
remove the broken link and the associated text.
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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As files got renamed, their references broke.
Manually fix a series of broken refs at the DT bindings.
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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Rename:
pinctrl-binding.txt -> pinctrl-bindings.txt
In order to match the current name of this file.
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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There were some file movements that changed the location for
some DT bindings. Fix them with:
scripts/documentation-file-ref-check --fix
After manually checking if the new file makes sense.
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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The specified locations are not right. Fix the wildcard logic
to point to the correct directories.
Without that, get-maintainer won't get things right:
$ ./scripts/get_maintainer.pl --no-git-fallback --no-r --no-n --no-l -f Documentation/devicetree/bindings/arm/cpu-enable-method/nuvoton,npcm750-smp
[email protected] (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
[email protected] (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
After the patch, it will properly point to NPCM arch maintainers:
$ ./scripts/get_maintainer.pl --no-git-fallback --no-r --no-n --no-l -f Documentation/devicetree/bindings/arm/cpu-enable-method/nuvoton,npcm750-smp
[email protected] (supporter:ARM/NUVOTON NPCM ARCHITECTURE)
[email protected] (supporter:ARM/NUVOTON NPCM ARCHITECTURE)
[email protected] (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
[email protected] (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
Cc: Avi Fishman <[email protected]>
Cc: Tomer Maimon <[email protected]>
Cc: Patrick Venture <[email protected]>
Cc: Nancy Yuen <[email protected]>
Cc: Brendan Higgins <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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Those files got a manufacturer's name prepended and were moved around.
Adjust their references accordingly.
Also, due those movements, Documentation/devicetree/bindings/video
doesn't exist anymore.
Cc: David Airlie <[email protected]>
Cc: David Lechner <[email protected]>
Cc: Peter Senna Tschudin <[email protected]>
Cc: Martin Donnelly <[email protected]>
Cc: Martyn Welch <[email protected]>
Cc: Stefan Agner <[email protected]>
Cc: Alison Wang <[email protected]>
Cc: Eric Anholt <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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The alsa parameters file was renamed to alsa-configuration.rst.
With regards to OSS, it got retired as a hole by at changeset
727dede0ba8a ("sound: Retire OSS"). So, it doesn't make sense
to keep mentioning it at kernel-parameters.txt.
Fixes: 727dede0ba8a ("sound: Retire OSS")
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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The location pointed there is missing "bindings/" on its path.
Acked-by: Srinivas Kandagatla <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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As we move stuff around, some doc references are broken. Fix some of
them via this script:
./scripts/documentation-file-ref-check --fix
Manually checked that produced results are valid.
Acked-by: Matthias Brugger <[email protected]>
Acked-by: Takashi Iwai <[email protected]>
Acked-by: Jeff Kirsher <[email protected]>
Acked-by: Guenter Roeck <[email protected]>
Acked-by: Miguel Ojeda <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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Some files, like tools/memory-model/README has references to
a Documentation file that is locale to it. Handle references
that are relative to them too.
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
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