Commit Graph

424 Commits

Author SHA1 Message Date
Saravana Kannan
8375e74f2b driver core: Add fw_devlink kernel commandline option
fwnode_operations.add_links allows creating device links from
information provided by firmware.

fwnode_operations.add_links is currently implemented only by
OF/devicetree code and a specific case of efi. However, there's nothing
preventing ACPI or other firmware types from implementing it.

The OF implementation is currently controlled by a kernel commandline
parameter called of_devlink.

Since this feature is generic isn't limited to OF, add a generic
fw_devlink kernel commandline parameter to control this feature across
firmware types.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200222014038.180923-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-04 17:58:48 +01:00
Saravana Kannan
1745d299af driver core: Reevaluate dev->links.need_for_probe as suppliers are added
A previous patch 03324507e6 ("driver core: Allow
fwnode_operations.add_links to differentiate errors") forgot to update
all call sites to fwnode_operations.add_links. This patch fixes that.

Legend:
-> Denotes RHS is an optional/potential supplier for LHS
=> Denotes RHS is a mandatory supplier for LHS

Example:

Device A => Device X
Device A -> Device Y

Before this patch:
1. Device A is added.
2. Device A is marked as waiting for mandatory suppliers
3. Device X is added
4. Device A is left marked as waiting for mandatory suppliers

Step 4 is wrong since all mandatory suppliers of Device A have been
added.

After this patch:
1. Device A is added.
2. Device A is marked as waiting for mandatory suppliers
3. Device X is added
4. Device A is no longer considered as waiting for mandatory suppliers

This is the correct behavior.

Fixes: 03324507e6 ("driver core: Allow fwnode_operations.add_links to differentiate errors")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200222014038.180923-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-04 17:58:47 +01:00
Saravana Kannan
26e77708fd driver core: Allow device link operations inside sync_state()
Some sync_state() implementations might need to call APIs that in turn
make calls to device link APIs. So, do the sync_state() callbacks
without holding the device link lock.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20191114225646.251277-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-15 10:06:54 +08:00
Saravana Kannan
03324507e6 driver core: Allow fwnode_operations.add_links to differentiate errors
When add_links() still has suppliers that it needs to link to in the
future, this patch allows it to differentiate between suppliers that are
needed for probing vs suppliers that are needed for sync_state()
correctness.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-02 18:05:18 +01:00
Saravana Kannan
bcbbcfd572 driver core: Allow a device to wait on optional suppliers
Before this change, if a device is waiting on suppliers, it's assumed
that all those suppliers are needed for the device to probe
successfully. This change allows marking a devices as waiting only on
optional suppliers. This allows a device to wait on suppliers (and link
to them as soon as they are available) without preventing the device
from being probed.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-02 18:05:17 +01:00
Saravana Kannan
05ef983e0d driver core: Add device link support for SYNC_STATE_ONLY flag
Parent devices might need to create "proxy" device links from themselves
to supplier devices to make sure the supplier devices don't get a
sync_state() before the child consumer devices get a chance to add
device links to the supplier devices.

However, the parent device has no real dependency on the supplier device
and probing, suspend/resume or runtime PM don't need to be affected by
the supplier device.  To capture these cases, create a SYNC_STATE_ONLY
device link flag that only affects sync_state() behavior and doesn't
affect probing, suspend/resume or runtime PM.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-02 18:05:17 +01:00
Greg Kroah-Hartman
8f677bc819 Merge 5.4-rc5 into driver-core-next
We want the sysfs fix in here as well to build on top of.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-27 18:54:13 +01:00
Rafael J. Wysocki
65650b3513 cpufreq: Avoid cpufreq_suspend() deadlock on system shutdown
It is incorrect to set the cpufreq syscore shutdown callback pointer
to cpufreq_suspend(), because that function cannot be run in the
syscore stage of system shutdown for two reasons: (a) it may attempt
to carry out actions depending on devices that have already been shut
down at that point and (b) the RCU synchronization carried out by it
may not be able to make progress then.

The latter issue has been present since commit 45975c7d21 ("rcu:
Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds"),
but the former one has been there since commit 90de2a4aa9 ("cpufreq:
suspend cpufreq governors on shutdown") regardless.

Fix that by dropping cpufreq_syscore_ops altogether and making
device_shutdown() call cpufreq_suspend() directly before shutting
down devices, which is along the lines of what system-wide power
management does.

Fixes: 45975c7d21 ("rcu: Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds")
Fixes: 90de2a4aa9 ("cpufreq: suspend cpufreq governors on shutdown")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
2019-10-10 11:11:17 +02:00
Saravana Kannan
fc5a251d0f driver core: Add sync_state driver/bus callback
This sync_state driver/bus callback is called once all the consumers
of a supplier have probed successfully.

This allows the supplier device's driver/bus to sync the supplier
device's state to the software state with the guarantee that all the
consumers are actively managing the resources provided by the supplier
device.

To maintain backwards compatibility and ease transition from existing
frameworks and resource cleanup schemes, late_initcall_sync is the
earliest when the sync_state callback might be called.

There is no upper bound on the time by which the sync_state callback
has to be called. This is because if a consumer device never probes,
the supplier has to maintain its resources in the state left by the
bootloader. For example, if the bootloader leaves the display
backlight at a fixed voltage and the backlight driver is never probed,
you don't want the backlight to ever be turned off after boot up.

Also, when multiple devices are added after kernel init, some
suppliers could be added before their consumer devices get added. In
these instances, the supplier devices could get their sync_state
callback called right after they probe because the consumers devices
haven't had a chance to create device links to the suppliers.

To handle this correctly, this change also provides APIs to
pause/resume sync state callbacks so that when multiple devices are
added, their sync_state callback evaluation can be postponed to happen
after all of them are added.

kbuild test robot reported missing documentation for device.state_synced
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-04 17:30:19 +02:00
Saravana Kannan
e2ae9bcc4a driver core: Add support for linking devices during device addition
The firmware corresponding to a device (dev.fwnode) might be able to
provide functional dependency information between a device and its
supplier and consumer devices.  Tracking this functional dependency
allows optimizing device probe order and informing a supplier when all
its consumers have probed (and thereby actively managing their
resources).

The existing device links feature allows tracking and using
supplier-consumer relationships. So, this patch adds the add_links()
fwnode callback to allow firmware to create device links for each
device as the device is added.

However, when consumer devices are added, they might not have a supplier
device to link to despite needing mandatory resources/functionality from
one or more suppliers. A waiting_for_suppliers list is created to track
such consumers and retry linking them when new devices get added.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-04 17:29:50 +02:00
Saravana Kannan
372a67c0c5 driver core: Add fwnode_to_dev() to look up device from fwnode
It's often useful to look up a device that corresponds to a fwnode. So
add an API to do that irrespective of the bus on which the device has
been added to.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-04 17:29:50 +02:00
Linus Torvalds
1f7d290a72 Driver core patches for 5.4-rc1
Here is the big driver core update for 5.4-rc1.
 
 There was a bit of a churn in here, with a number of core and OF
 platform patches being added to the tree, and then after much discussion
 and review and a day-long in-person meeting, they were decided to be
 reverted and a new set of patches is currently being reviewed on the
 mailing list.
 
 Other than that churn, there are two "persistent" branches in here that
 other trees will be pulling in as well during the merge window.  One
 branch to add support for drivers to have the driver core automatically
 add sysfs attribute files when a driver is bound to a device so that the
 driver doesn't have to manually do it (and then clean it up, as it
 always gets it wrong).
 
 There's another branch in here for generic lookup helpers for the driver
 core that lots of busses are starting to use.  That's the majority of
 the non-driver-core changes in this patch series.
 
 There's also some on-going debugfs file creation cleanup that has been
 slowly happening over the past few releases, with the goal to hopefully
 get that done sometime next year.
 
 All of these have been in linux-next for a while now with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg Kroah-Hartman:
 "Here is the big driver core update for 5.4-rc1.

  There was a bit of a churn in here, with a number of core and OF
  platform patches being added to the tree, and then after much
  discussion and review and a day-long in-person meeting, they were
  decided to be reverted and a new set of patches is currently being
  reviewed on the mailing list.

  Other than that churn, there are two "persistent" branches in here
  that other trees will be pulling in as well during the merge window.
  One branch to add support for drivers to have the driver core
  automatically add sysfs attribute files when a driver is bound to a
  device so that the driver doesn't have to manually do it (and then
  clean it up, as it always gets it wrong).

  There's another branch in here for generic lookup helpers for the
  driver core that lots of busses are starting to use. That's the
  majority of the non-driver-core changes in this patch series.

  There's also some on-going debugfs file creation cleanup that has been
  slowly happening over the past few releases, with the goal to
  hopefully get that done sometime next year.

  All of these have been in linux-next for a while now with no reported
  issues"

[ Note that the above-mentioned generic lookup helpers branch was
  already brought in by the LED merge (commit 4feaab05dc) that had
  shared it.

  Also note that that common branch introduced an i2c bug due to a bad
  conversion, which got fixed here. - Linus ]

* tag 'driver-core-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (49 commits)
  coccinelle: platform_get_irq: Fix parse error
  driver-core: add include guard to linux/container.h
  sysfs: add BIN_ATTR_WO() macro
  driver core: platform: Export platform_get_irq_optional()
  hwmon: pwm-fan: Use platform_get_irq_optional()
  driver core: platform: Introduce platform_get_irq_optional()
  Revert "driver core: Add support for linking devices during device addition"
  Revert "driver core: Add edit_links() callback for drivers"
  Revert "of/platform: Add functional dependency link from DT bindings"
  Revert "driver core: Add sync_state driver/bus callback"
  Revert "of/platform: Pause/resume sync state during init and of_platform_populate()"
  Revert "of/platform: Create device links for all child-supplier depencencies"
  Revert "of/platform: Don't create device links for default busses"
  Revert "of/platform: Fix fn definitons for of_link_is_valid() and of_link_property()"
  Revert "of/platform: Fix device_links_supplier_sync_state_resume() warning"
  Revert "of/platform: Disable generic device linking code for PowerPC"
  devcoredump: fix typo in comment
  devcoredump: use memory_read_from_buffer
  of/platform: Disable generic device linking code for PowerPC
  device.h: Fix warnings for mismatched parameter names in comments
  ...
2019-09-18 10:04:39 -07:00
Linus Torvalds
4feaab05dc LED updates for 5.4-rc1
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Merge tag 'leds-for-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED updates from Jacek Anaszewski:
 "In this cycle we've finally managed to contribute the patch set
  sorting out LED naming issues. Besides that there are many changes
  scattered among various LED class drivers and triggers.

  LED naming related improvements:

   - add new 'function' and 'color' fwnode properties and deprecate
     'label' property which has been frequently abused for conveying
     vendor specific names that have been available in sysfs anyway

   - introduce a set of standard LED_FUNCTION* definitions

   - introduce a set of standard LED_COLOR_ID* definitions

   - add a new {devm_}led_classdev_register_ext() API with the
     capability of automatic LED name composition basing on the
     properties available in the passed fwnode; the function is
     backwards compatible in a sense that it uses 'label' data, if
     present in the fwnode, for creating LED name

   - add tools/leds/get_led_device_info.sh script for retrieving LED
     vendor, product and bus names, if applicable; it also performs
     basic validation of an LED name

   - update following drivers and their DT bindings to use the new LED
     registration API:

        - leds-an30259a, leds-gpio, leds-as3645a, leds-aat1290, leds-cr0014114,
          leds-lm3601x, leds-lm3692x, leds-lp8860, leds-lt3593, leds-sc27xx-blt

  Other LED class improvements:

   - replace {devm_}led_classdev_register() macros with inlines

   - allow to call led_classdev_unregister() unconditionally

   - switch to use fwnode instead of be stuck with OF one

  LED triggers improvements:

   - led-triggers:
        - fix dereferencing of null pointer
        - fix a memory leak bug

   - ledtrig-gpio:
        - GPIO 0 is valid

  Drop superseeded apu2/3 support from leds-apu since for apu2+ a newer,
  more complete driver exists, based on a generic driver for the AMD
  SOCs gpio-controller, supporting LEDs as well other devices:

   - drop profile field from priv data

   - drop iosize field from priv data

   - drop enum_apu_led_platform_types

   - drop superseeded apu2/3 led support

   - add pr_fmt prefix for better log output

   - fix error message on probing failure

  Other misc fixes and improvements to existing LED class drivers:

   - leds-ns2, leds-max77650:
        - add of_node_put() before return

   - leds-pwm, leds-is31fl32xx:
        - use struct_size() helper

   - leds-lm3697, leds-lm36274, leds-lm3532:
        - switch to use fwnode_property_count_uXX()

   - leds-lm3532:
        - fix brightness control for i2c mode
        - change the define for the fs current register
        - fixes for the driver for stability
        - add full scale current configuration
        - dt: Add property for full scale current.
        - avoid potentially unpaired regulator calls
        - move static keyword to the front of declarations
        - fix optional led-max-microamp prop error handling

   - leds-max77650:
        - add of_node_put() before return
        - add MODULE_ALIAS()
        - Switch to fwnode property API

   - leds-as3645a:
        - fix misuse of strlcpy

   - leds-netxbig:
        - add of_node_put() in netxbig_leds_get_of_pdata()
        - remove legacy board-file support

   - leds-is31fl319x:
        - simplify getting the adapter of a client

   - leds-ti-lmu-common:
        - fix coccinelle issue
        - move static keyword to the front of declaration

   - leds-syscon:
        - use resource managed variant of device register

   - leds-ktd2692:
        - fix a typo in the name of a constant

   - leds-lp5562:
        - allow firmware files up to the maximum length

   - leds-an30259a:
        - fix typo

   - leds-pca953x:
        - include the right header"

* tag 'leds-for-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds: (72 commits)
  leds: lm3532: Fix optional led-max-microamp prop error handling
  led: triggers: Fix dereferencing of null pointer
  leds: ti-lmu-common: Move static keyword to the front of declaration
  leds: lm3532: Move static keyword to the front of declarations
  leds: trigger: gpio: GPIO 0 is valid
  leds: pwm: Use struct_size() helper
  leds: is31fl32xx: Use struct_size() helper
  leds: ti-lmu-common: Fix coccinelle issue in TI LMU
  leds: lm3532: Avoid potentially unpaired regulator calls
  leds: syscon: Use resource managed variant of device register
  leds: Replace {devm_}led_classdev_register() macros with inlines
  leds: Allow to call led_classdev_unregister() unconditionally
  leds: lm3532: Add full scale current configuration
  dt: lm3532: Add property for full scale current.
  leds: lm3532: Fixes for the driver for stability
  leds: lm3532: Change the define for the fs current register
  leds: lm3532: Fix brightness control for i2c mode
  leds: Switch to use fwnode instead of be stuck with OF one
  leds: max77650: Switch to fwnode property API
  led: triggers: Fix a memory leak bug
  ...
2019-09-17 18:40:42 -07:00
Greg Kroah-Hartman
bfb3943bed Revert "driver core: Add support for linking devices during device addition"
This reverts commit 5302dd7dd0.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged.  It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-27 21:41:16 +02:00
Greg Kroah-Hartman
33cbfe5449 Revert "driver core: Add edit_links() callback for drivers"
This reverts commit 134b23eec9.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged.  It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-27 21:41:06 +02:00
Greg Kroah-Hartman
bcca686c11 Revert "driver core: Add sync_state driver/bus callback"
This reverts commit 8f8184d6bf.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged.  It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-27 21:40:50 +02:00
Ingo Molnar
6c06b66e95 Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU and LKMM changes from Paul E. McKenney:

 - A few more RCU flavor consolidation cleanups.

 - Miscellaneous fixes.

 - Updates to RCU's list-traversal macros improving lockdep usability.

 - Torture-test updates.

 - Forward-progress improvements for no-CBs CPUs: Avoid ignoring
   incoming callbacks during grace-period waits.

 - Forward-progress improvements for no-CBs CPUs: Use ->cblist
   structure to take advantage of others' grace periods.

 - Also added a small commit that avoids needlessly inflicting
   scheduler-clock ticks on callback-offloaded CPUs.

 - Forward-progress improvements for no-CBs CPUs: Reduce contention
   on ->nocb_lock guarding ->cblist.

 - Forward-progress improvements for no-CBs CPUs: Add ->nocb_bypass
   list to further reduce contention on ->nocb_lock guarding ->cblist.

 - LKMM updates.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-08-22 20:52:04 +02:00
Joel Fernandes (Google)
c2fa1e1bfa driver/core: Convert to use built-in RCU list checking
This commit applies the consolidated hlist_for_each_entry_rcu() support
for lockdep conditions.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-08-13 14:28:47 -07:00
Greg Kroah-Hartman
e6aa640eb2 Merge 5.3-rc4 into driver-core-next
We need the driver core fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-12 07:37:39 +02:00
Linus Torvalds
36e630ed98 Driver core fixes for 5.3-rc4
Here are 2 small fixes for some driver core issues that have been
 reported.  There is also a kernfs "fix" here, which was then reverted
 because it was found to cause problems in linux-next.
 
 The driver core fixes both resolve reported issues, one with gpioint
 stuff that showed up in 5.3-rc1, and the other finally (and hopefully)
 resolves a very long standing race when removing glue directories.  It's
 nice to get that issue finally resolved and the developers involved
 should be applauded for the persistence it took to get this patch
 finally accepted.
 
 All of these have been in linux-next for a while with no reported
 issues.  Well, the one reported issue, hence the revert :)
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are two small fixes for some driver core issues that have been
  reported. There is also a kernfs "fix" here, which was then reverted
  because it was found to cause problems in linux-next.

  The driver core fixes both resolve reported issues, one with gpioint
  stuff that showed up in 5.3-rc1, and the other finally (and hopefully)
  resolves a very long standing race when removing glue directories.
  It's nice to get that issue finally resolved and the developers
  involved should be applauded for the persistence it took to get this
  patch finally accepted.

  All of these have been in linux-next for a while with no reported
  issues. Well, the one reported issue, hence the revert :)"

* tag 'driver-core-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  Revert "kernfs: fix memleak in kernel_ops_readdir()"
  kernfs: fix memleak in kernel_ops_readdir()
  driver core: Fix use-after-free and double free on glue directory
  driver core: platform: return -ENXIO for missing GpioInt
2019-08-10 12:20:02 -07:00
Saravana Kannan
8f8184d6bf driver core: Add sync_state driver/bus callback
This sync_state driver/bus callback is called once all the consumers
of a supplier have probed successfully.

This allows the supplier device's driver/bus to sync the supplier
device's state to the software state with the guarantee that all the
consumers are actively managing the resources provided by the supplier
device.

To maintain backwards compatibility and ease transition from existing
frameworks and resource cleanup schemes, late_initcall_sync is the
earliest when the sync_state callback might be called.

There is no upper bound on the time by which the sync_state callback
has to be called. This is because if a consumer device never probes,
the supplier has to maintain its resources in the state left by the
bootloader. For example, if the bootloader leaves the display
backlight at a fixed voltage and the backlight driver is never probed,
you don't want the backlight to ever be turned off after boot up.

Also, when multiple devices are added after kernel init, some
suppliers could be added before their consumer devices get added. In
these instances, the supplier devices could get their sync_state
callback called right after they probe because the consumers devices
haven't had a chance to create device links to the suppliers.

To handle this correctly, this change also provides APIs to
pause/resume sync state callbacks so that when multiple devices are
added, their sync_state callback evaluation can be postponed to happen
after all of them are added.

kbuild test robot reported missing documentation for device.state_synced
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-01 16:04:14 +02:00
Saravana Kannan
134b23eec9 driver core: Add edit_links() callback for drivers
The driver core/bus adding supplier-consumer dependencies by default
enables functional dependencies to be tracked correctly even when the
consumer devices haven't had their drivers registered or loaded (if they
are modules).

However, when the bus incorrectly adds dependencies that it shouldn't
have added, the devices might never probe.

For example, if device-C is a consumer of device-S and they have
phandles to each other in DT, the following could happen:

1.  Device-S get added first.
2.  The bus add_links() callback will (incorrectly) try to link it as
    a consumer of device-C.
3.  Since device-C isn't present, device-S will be put in
    "waiting-for-supplier" list.
4.  Device-C gets added next.
5.  All devices in "waiting-for-supplier" list are retried for linking.
6.  Device-S gets linked as consumer to Device-C.
7.  The bus add_links() callback will (correctly) try to link it as
    a consumer of device-S.
8.  This isn't allowed because it would create a cyclic device links.

Neither devices will get probed since the supplier is marked as
dependent on the consumer. And the consumer will never probe because the
consumer can't get resources from the supplier.

Without this patch, things stay in this broken state. However, with this
patch, the execution will continue like this:

9.  Device-C's driver is loaded.
10. Device-C's driver removes Device-S as a consumer of Device-C.
11. Device-C's driver adds Device-C as a consumer of Device-S.
12. Device-S probes.
14. Device-C probes.

kbuild test robot reported missing documentation for device.has_edit_links
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-01 16:04:13 +02:00
Saravana Kannan
5302dd7dd0 driver core: Add support for linking devices during device addition
When devices are added, the bus might want to create device links to track
functional dependencies between supplier and consumer devices. This
tracking of supplier-consumer relationship allows optimizing device probe
order and tracking whether all consumers of a supplier are active. The
add_links bus callback is added to support this.

However, when consumer devices are added, they might not have a supplier
device to link to despite needing mandatory resources/functionality from
one or more suppliers. A waiting_for_suppliers list is created to track
such consumers and retry linking them when new devices get added.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-01 16:04:13 +02:00
Muchun Song
ac43432cb1 driver core: Fix use-after-free and double free on glue directory
There is a race condition between removing glue directory and adding a new
device under the glue dir. It can be reproduced in following test:

CPU1:                                         CPU2:

device_add()
  get_device_parent()
    class_dir_create_and_add()
      kobject_add_internal()
        create_dir()    // create glue_dir

                                              device_add()
                                                get_device_parent()
                                                  kobject_get() // get glue_dir

device_del()
  cleanup_glue_dir()
    kobject_del(glue_dir)

                                                kobject_add()
                                                  kobject_add_internal()
                                                    create_dir() // in glue_dir
                                                      sysfs_create_dir_ns()
                                                        kernfs_create_dir_ns(sd)

      sysfs_remove_dir() // glue_dir->sd=NULL
      sysfs_put()        // free glue_dir->sd

                                                          // sd is freed
                                                          kernfs_new_node(sd)
                                                            kernfs_get(glue_dir)
                                                            kernfs_add_one()
                                                            kernfs_put()

Before CPU1 remove last child device under glue dir, if CPU2 add a new
device under glue dir, the glue_dir kobject reference count will be
increase to 2 via kobject_get() in get_device_parent(). And CPU2 has
been called kernfs_create_dir_ns(), but not call kernfs_new_node().
Meanwhile, CPU1 call sysfs_remove_dir() and sysfs_put(). This result in
glue_dir->sd is freed and it's reference count will be 0. Then CPU2 call
kernfs_get(glue_dir) will trigger a warning in kernfs_get() and increase
it's reference count to 1. Because glue_dir->sd is freed by CPU1, the next
call kernfs_add_one() by CPU2 will fail(This is also use-after-free)
and call kernfs_put() to decrease reference count. Because the reference
count is decremented to 0, it will also call kmem_cache_free() to free
the glue_dir->sd again. This will result in double free.

In order to avoid this happening, we also should make sure that kernfs_node
for glue_dir is released in CPU1 only when refcount for glue_dir kobj is
1 to fix this race.

The following calltrace is captured in kernel 4.14 with the following patch
applied:

commit 726e410979 ("drivers: core: Remove glue dirs from sysfs earlier")

--------------------------------------------------------------------------
[    3.633703] WARNING: CPU: 4 PID: 513 at .../fs/kernfs/dir.c:494
                Here is WARN_ON(!atomic_read(&kn->count) in kernfs_get().
....
[    3.633986] Call trace:
[    3.633991]  kernfs_create_dir_ns+0xa8/0xb0
[    3.633994]  sysfs_create_dir_ns+0x54/0xe8
[    3.634001]  kobject_add_internal+0x22c/0x3f0
[    3.634005]  kobject_add+0xe4/0x118
[    3.634011]  device_add+0x200/0x870
[    3.634017]  _request_firmware+0x958/0xc38
[    3.634020]  request_firmware_into_buf+0x4c/0x70
....
[    3.634064] kernel BUG at .../mm/slub.c:294!
                Here is BUG_ON(object == fp) in set_freepointer().
....
[    3.634346] Call trace:
[    3.634351]  kmem_cache_free+0x504/0x6b8
[    3.634355]  kernfs_put+0x14c/0x1d8
[    3.634359]  kernfs_create_dir_ns+0x88/0xb0
[    3.634362]  sysfs_create_dir_ns+0x54/0xe8
[    3.634366]  kobject_add_internal+0x22c/0x3f0
[    3.634370]  kobject_add+0xe4/0x118
[    3.634374]  device_add+0x200/0x870
[    3.634378]  _request_firmware+0x958/0xc38
[    3.634381]  request_firmware_into_buf+0x4c/0x70
--------------------------------------------------------------------------

Fixes: 726e410979 ("drivers: core: Remove glue dirs from sysfs earlier")
Signed-off-by: Muchun Song <smuchun@gmail.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Link: https://lore.kernel.org/r/20190727032122.24639-1-smuchun@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 18:44:47 +02:00
Greg Kroah-Hartman
f87da58b79 Merge branch 'generic_lookup_helpers' into driver-core-next
This was on a separate branch so that others can pull it in.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:26:39 +02:00
Suzuki K Poulose
6bf85ba9e5 drivers: Add generic helper to match any device
Add a generic helper to match any/all devices. Using this
introduce new wrappers {bus/driver/class}_find_next_device().

Cc: Elie Morisse <syniurge@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Nehal Shah <nehal-bakulchandra.shah@amd.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Shyam Sundar S K <shyam-sundar.s-k@amd.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # PCI
Link: https://lore.kernel.org/r/20190723221838.12024-7-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:07:42 +02:00
Suzuki K Poulose
00500147cb drivers: Introduce device lookup variants by ACPI_COMPANION device
Add a generic helper to match a device by the ACPI_COMPANION device
and provide wrappers for the device lookup APIs.

Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: linux-i2c@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C parts
Link: https://lore.kernel.org/r/20190723221838.12024-6-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:07:42 +02:00
Suzuki K Poulose
4495dfdd61 drivers: Introduce device lookup variants by device type
Add a helper to match a device by its type and provide wrappers
for {bus/class/driver}_find_device() APIs.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-5-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:07:42 +02:00
Suzuki K Poulose
67843bbaf3 drivers: Introduce device lookup variants by fwnode
Add a helper to match the firmware node handle of a device and provide
wrappers for {bus/class/driver}_find_device() APIs to avoid proliferation
of duplicate custom match functions.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-usb@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20190723221838.12024-4-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:07:42 +02:00
Suzuki K Poulose
6cda08a20d drivers: Introduce device lookup variants by name
Add a helper to match the device name for device lookup. Also
reuse this generic exported helper for the existing bus_find_device_by_name().
and add similar variants for driver/class.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-leds@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20190723221838.12024-2-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:07:41 +02:00
Rafael J. Wysocki
fb583c8eee driver core: Fix creation of device links with PM-runtime flags
After commit 515db266a9 ("driver core: Remove device link creation
limitation"), if PM-runtime flags are passed to device_link_add(), it
will fail (returning NULL) due to an overly restrictive flags check
introduced by that commit.

Fix this issue by extending the check in question to cover the
PM-runtime flags too.

Fixes: 515db266a9 ("driver core: Remove device link creation limitation")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/7674989.cD04D8YV3U@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 12:34:39 +02:00
Linus Torvalds
523634db14 libnvdimm fixes v5.3-rc2
- Fix duplicate device_unregister() calls (multiple threads competing to
   do unregister work when scheduling device removal from a sysfs attribute
   of the self-same device).
 
 - Fix badblocks registration order bug. Ensure region badblocks are
   initialized in advance of namespace registration.
 
 - Fix a deadlock between the bus lock and probe operations.
 
 - Export device-core infrastructure to coordinate async operations via
   the device ->dead state.
 
 - Add device-core infrastructure to validate device_lock() usage with
   lockdep.
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Merge tag 'libnvdimm-fixes-5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm fixes from Dan Williams:
 "A collection of locking and async operations fixes for v5.3-rc2. These
  had been soaking in a branch targeting the merge window, but missed
  due to a regression hunt. This fixed up version has otherwise been in
  -next this past week with no reported issues.

  In order to gain confidence in the locking changes the pull also
  includes a debug / instrumentation patch to enable lockdep coverage
  for libnvdimm subsystem operations that depend on the device_lock for
  exclusion. As mentioned in the changelog it is a hack, but it works
  and documents the locking expectations of the sub-system in a way that
  others can use lockdep to verify. The driver core touches got an ack
  from Greg.

  Summary:

   - Fix duplicate device_unregister() calls (multiple threads competing
     to do unregister work when scheduling device removal from a sysfs
     attribute of the self-same device).

   - Fix badblocks registration order bug. Ensure region badblocks are
     initialized in advance of namespace registration.

   - Fix a deadlock between the bus lock and probe operations.

   - Export device-core infrastructure to coordinate async operations
     via the device ->dead state.

   - Add device-core infrastructure to validate device_lock() usage with
     lockdep"

* tag 'libnvdimm-fixes-5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  driver-core, libnvdimm: Let device subsystems add local lockdep coverage
  libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock
  libnvdimm/bus: Stop holding nvdimm_bus_list_mutex over __nd_ioctl()
  libnvdimm/bus: Prepare the nd_ioctl() path to be re-entrant
  libnvdimm/region: Register badblocks before namespaces
  libnvdimm/bus: Prevent duplicate device_unregister() calls
  drivers/base: Introduce kill_device()
2019-07-27 08:25:51 -07:00
Rafael J. Wysocki
515db266a9 driver core: Remove device link creation limitation
If device_link_add() is called for a consumer/supplier pair with an
existing device link between them and the existing link's type is
not in agreement with the flags passed to that function by its
caller, NULL will be returned.  That is seriously inconvenient,
because it forces the callers of device_link_add() to worry about
what others may or may not do even if that is not relevant to them
for any other reasons.

It turns out, however, that this limitation can be made go away
relatively easily.

The underlying observation is that if DL_FLAG_STATELESS has been
passed to device_link_add() in flags for the given consumer/supplier
pair at least once, calling either device_link_del() or
device_link_remove() to release the link returned by it should work,
but there are no other requirements associated with that flag.  In
turn, if at least one of the callers of device_link_add() for the
given consumer/supplier pair has not passed DL_FLAG_STATELESS to it
in flags, the driver core should track the status of the link and act
on it as appropriate (ie. the link should be treated as "managed").
This means that DL_FLAG_STATELESS needs to be set for managed device
links and it should be valid to call device_link_del() or
device_link_remove() to drop references to them in certain
sutiations.

To allow that to happen, introduce a new (internal) device link flag
called DL_FLAG_MANAGED and make device_link_add() set it automatically
whenever DL_FLAG_STATELESS is not passed to it.  Also make it take
additional references to existing device links that were previously
stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED
unset) and will need to be managed going forward and initialize
their status (which has been DL_STATE_NONE so far).

Accordingly, when a managed device link is dropped automatically
by the driver core, make it clear DL_FLAG_MANAGED, reset the link's
status back to DL_STATE_NONE and drop the reference to it associated
with DL_FLAG_MANAGED instead of just deleting it right away (to
allow it to stay around in case it still needs to be released
explicitly by someone).

With that, since setting DL_FLAG_STATELESS doesn't mean that the
device link in question is not managed any more, replace all of the
status-tracking checks against DL_FLAG_STATELESS with analogous
checks against DL_FLAG_MANAGED and update the documentation to
reflect these changes.

While at it, make device_link_add() reject flags that it does not
recognize, including DL_FLAG_MANAGED.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Review-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-25 13:31:18 +02:00
Dan Williams
87a30e1f05 driver-core, libnvdimm: Let device subsystems add local lockdep coverage
For good reason, the standard device_lock() is marked
lockdep_set_novalidate_class() because there is simply no sane way to
describe the myriad ways the device_lock() ordered with other locks.
However, that leaves subsystems that know their own local device_lock()
ordering rules to find lock ordering mistakes manually. Instead,
introduce an optional / additional lockdep-enabled lock that a subsystem
can acquire in all the same paths that the device_lock() is acquired.

A conversion of the NFIT driver and NVDIMM subsystem to a
lockdep-validate device_lock() scheme is included. The
debug_nvdimm_lock() implementation implements the correct lock-class and
stacking order for the libnvdimm device topology hierarchy.

Yes, this is a hack, but hopefully it is a useful hack for other
subsystems device_lock() debug sessions. Quoting Greg:

    "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up
     using it as much as anything else, so user beware :)

     I don't object to it if it makes things easier for you to debug."

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
2019-07-18 16:23:27 -07:00
Dan Williams
00289cd876 drivers/base: Introduce kill_device()
The libnvdimm subsystem arranges for devices to be destroyed as a result
of a sysfs operation. Since device_unregister() cannot be called from
an actively running sysfs attribute of the same device libnvdimm
arranges for device_unregister() to be performed in an out-of-line async
context.

The driver core maintains a 'dead' state for coordinating its own racing
async registration / de-registration requests. Rather than add local
'dead' state tracking infrastructure to libnvdimm device objects, export
the existing state tracking via a new kill_device() helper.

The kill_device() helper simply marks the device as dead, i.e. that it
is on its way to device_del(), or returns that the device was already
dead. This can be used in advance of calling device_unregister() for
subsystems like libnvdimm that might need to handle multiple user
threads racing to delete a device.

This refactoring does not change any behavior, but it is a pre-requisite
for follow-on fixes and therefore marked for -stable.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Fixes: 4d88a97aa9 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...")
Cc: <stable@vger.kernel.org>
Tested-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/156341207332.292348.14959761496009347574.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-07-18 16:21:01 -07:00
Linus Torvalds
f632a8170a Driver Core and debugfs changes for 5.3-rc1
Here is the "big" driver core and debugfs changes for 5.3-rc1
 
 It's a lot of different patches, all across the tree due to some api
 changes and lots of debugfs cleanups.  Because of this, there is going
 to be some merge issues with your tree at the moment, I'll follow up
 with the expected resolutions to make it easier for you.
 
 Other than the debugfs cleanups, in this set of changes we have:
 	- bus iteration function cleanups (will cause build warnings
 	  with s390 and coresight drivers in your tree)
 	- scripts/get_abi.pl tool to display and parse Documentation/ABI
 	  entries in a simple way
 	- cleanups to Documenatation/ABI/ entries to make them parse
 	  easier due to typos and other minor things
 	- default_attrs use for some ktype users
 	- driver model documentation file conversions to .rst
 	- compressed firmware file loading
 	- deferred probe fixes
 
 All of these have been in linux-next for a while, with a bunch of merge
 issues that Stephen has been patient with me for.  Other than the merge
 issues, functionality is working properly in linux-next :)
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and debugfs updates from Greg KH:
 "Here is the "big" driver core and debugfs changes for 5.3-rc1

  It's a lot of different patches, all across the tree due to some api
  changes and lots of debugfs cleanups.

  Other than the debugfs cleanups, in this set of changes we have:

   - bus iteration function cleanups

   - scripts/get_abi.pl tool to display and parse Documentation/ABI
     entries in a simple way

   - cleanups to Documenatation/ABI/ entries to make them parse easier
     due to typos and other minor things

   - default_attrs use for some ktype users

   - driver model documentation file conversions to .rst

   - compressed firmware file loading

   - deferred probe fixes

  All of these have been in linux-next for a while, with a bunch of
  merge issues that Stephen has been patient with me for"

* tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (102 commits)
  debugfs: make error message a bit more verbose
  orangefs: fix build warning from debugfs cleanup patch
  ubifs: fix build warning after debugfs cleanup patch
  driver: core: Allow subsystems to continue deferring probe
  drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT
  arch_topology: Remove error messages on out-of-memory conditions
  lib: notifier-error-inject: no need to check return value of debugfs_create functions
  swiotlb: no need to check return value of debugfs_create functions
  ceph: no need to check return value of debugfs_create functions
  sunrpc: no need to check return value of debugfs_create functions
  ubifs: no need to check return value of debugfs_create functions
  orangefs: no need to check return value of debugfs_create functions
  nfsd: no need to check return value of debugfs_create functions
  lib: 842: no need to check return value of debugfs_create functions
  debugfs: provide pr_fmt() macro
  debugfs: log errors when something goes wrong
  drivers: s390/cio: Fix compilation warning about const qualifiers
  drivers: Add generic helper to match by of_node
  driver_find_device: Unify the match function with class_find_device()
  bus_find_device: Unify the match callback with class_find_device
  ...
2019-07-12 12:24:03 -07:00
Suzuki K Poulose
65b6668234 drivers: Add generic helper to match by of_node
Add a helper to match device by the of_node. This will be later used
to provide wrappers to the device iterators for {bus/class/driver}_find_device().
Convert other users to reuse this new helper.

Cc: Alan Tull <atull@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: devicetree@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-fpga@vger.kernel.org
Cc: linux-i2c@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: Peter Rosin <peda@axentia.se>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-24 05:22:31 +02:00
Heikki Krogerus
dad9bb0178 driver core: Add helper device_find_child_by_name()
It looks like the child device is often matched with a name.
This introduces a helper that does it automatically.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-03 10:55:38 +02:00
Borislav Petkov
affada726c driver core: Clarify which counterparts to use to device_add()
It is not absolutely clear from the docs how the cleanup path after
device_add() should look like so spell it out explicitly.

No functional changes, just documentation.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 19:34:54 +02:00
Rafael J. Wysocki
36003d4cf5 driver core: Fix PM-runtime for links added during consumer probe
Commit 4c06c4e6cf ("driver core: Fix possible supplier PM-usage
counter imbalance") introduced a regression that causes suppliers
to be suspended prematurely for device links added during consumer
driver probe if the initial PM-runtime status of the consumer is
"suspended" and the consumer is resumed after adding the link and
before pm_runtime_put_suppliers() is called.  In that case,
pm_runtime_put_suppliers() will drop the rpm_active refcount for
the link by one and (since rpm_active is equal to two after the
preceding consumer resume) the supplier's PM-runtime usage counter
will be decremented, which may cause the supplier to suspend even
though the consumer's PM-runtime status is "active".

For this reason, partially revert commit 4c06c4e6cf as the problem
it tried to fix needs to be addressed somewhat differently, and
change pm_runtime_get_suppliers() and pm_runtime_put_suppliers() so
that the latter only drops rpm_active references acquired by the
former.  [This requires adding a new field to struct device_link,
but I coulnd't find a cleaner way to address the issue that would
work in all cases.]

This causes pm_runtime_put_suppliers() to effectively ignore device
links added during consumer probe, so device_link_add() doesn't need
to worry about ensuring that suppliers will remain active after
pm_runtime_put_suppliers() for links created with DL_FLAG_RPM_ACTIVE
set and it only needs to bump up rpm_active by one for those links,
so pm_runtime_active_link() is not necessary any more.

Fixes: 4c06c4e6cf ("driver core: Fix possible supplier PM-usage counter imbalance")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-20 11:18:07 +01:00
Rafael J. Wysocki
4c06c4e6cf driver core: Fix possible supplier PM-usage counter imbalance
If a stateless device link to a certain supplier with
DL_FLAG_PM_RUNTIME set in the flags is added and then removed by the
consumer driver's probe callback, the supplier's PM-runtime usage
counter will be nonzero after that which effectively causes the
supplier to remain "always on" going forward.

Namely, device_link_add() called to add the link invokes
device_link_rpm_prepare() which notices that the consumer driver is
probing, so it increments the supplier's PM-runtime usage counter
with the assumption that the link will stay around until
pm_runtime_put_suppliers() is called by driver_probe_device(),
but if the link goes away before that point, the supplier's
PM-runtime usage counter will remain nonzero.

To prevent that from happening, first rework pm_runtime_get_suppliers()
and pm_runtime_put_suppliers() to use the rpm_active refounts of device
links and make the latter only drop rpm_active and the supplier's
PM-runtime usage counter for each link by one, unless rpm_active is
one already for it.  Next, modify device_link_add() to bump up the
new link's rpm_active refcount and the suppliers PM-runtime usage
counter by two, to prevent pm_runtime_put_suppliers(), if it is
called subsequently, from suspending the supplier prematurely (in
case its PM-runtime usage counter goes down to 0 in there).

Due to the way rpm_put_suppliers() works, this change does not
affect runtime suspend of the consumer ends of new device links (or,
generally, device links for which DL_FLAG_PM_RUNTIME has just been
set).

Fixes: e2f3cd831a ("driver core: Fix handling of runtime PM flags in device_link_add()")
Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-13 09:09:57 +01:00
Rafael J. Wysocki
e7dd40105a driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER
Add a new device link flag, DL_FLAG_AUTOPROBE_CONSUMER, to request the
driver core to probe for a consumer driver automatically after binding
a driver to the supplier device on a persistent managed device link.

As unbinding the supplier driver on a managed device link causes the
consumer driver to be detached from its device automatically, this
flag provides a complementary mechanism which is needed to address
some "composite device" use cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
72175d4ea4 driver core: Make driver core own stateful device links
Even though stateful device links are managed by the driver core in
principle, their creators are allowed and sometimes even expected
to drop references to them via device_link_del() or
device_link_remove(), but that doesn't really play well with the
"persistent" link concept.

If "persistent" managed device links are created from driver
probe callbacks, device_link_add() called to do that will take a
new reference on the link each time the callback runs and those
references will never be dropped, which kind of isn't nice.

This issues arises because of the link reference counting carried
out by device_link_add() for existing links, but that is only done to
avoid deleting device links that may still be necessary, which
shouldn't be a concern for managed (stateful) links.  These device
links are managed by the driver core and whoever creates one of them
will need it at least as long as until the consumer driver is detached
from its device and deleting it may be left to the driver core just
fine.

For this reason, rework device_link_add() to apply the reference
counting to stateless links only and make device_link_del() and
device_link_remove() drop references to stateless links only too.
After this change, if called to add a stateful device link for
a consumer-supplier pair for which a stateful device link is
present already, device_link_add() will return the existing link
without incrementing its reference counter.  Accordingly,
device_link_del() and device_link_remove() will WARN() and do
nothing when called to drop a reference to a stateful link.  Thus,
effectively, all stateful device links will be owned by the driver
core.

In addition, clean up the handling of the link management flags,
DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER, so that
(a) they are never set at the same time and (b) if device_link_add()
is called for a consumer-supplier pair with an existing stateful link
between them, the flags of that link will be combined with the flags
passed to device_link_add() to ensure that the life time of the link
is sufficient for all of the callers of device_link_add() for the
same consumer-supplier pair.

Update the device_link_add() kerneldoc comment to reflect the
above changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
a1fdbfbb1d driver core: Do not call rpm_put_suppliers() in pm_runtime_drop_link()
Calling rpm_put_suppliers() from pm_runtime_drop_link() is excessive
as it affects all suppliers of the consumer device and not just the
one pointed to by the device link being dropped.  Worst case it may
cause the consumer device to stop working unexpectedly.  Moreover, in
principle it is racy with respect to runtime PM of the consumer
device.

To avoid these problems drop runtime PM references on the particular
supplier pointed to by the link in question only and do that after
the link has been dropped from the consumer device's list of links to
suppliers, which is in device_link_free().

Fixes: a0504aecba ("PM / runtime: Drop usage count for suppliers at device link removal")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
15cfb09416 driver core: Fix adding device links to probing suppliers
Currently, it is not valid to add a device link from a consumer
driver ->probe callback to a supplier that is still probing too, but
generally this is a valid use case.  For example, if the consumer has
just acquired a resource that can only be available if the supplier
is functional, adding a device link to that supplier right away
should be safe (and even desirable arguably), but device_link_add()
doesn't handle that case correctly and the initial state of the link
created by it is wrong then.

To address this problem, change the initial state of device links
added between a probing supplier and a probing consumer to
DL_STATE_CONSUMER_PROBE and update device_links_driver_bound() to
skip such links on the supplier side.

With this change, if the supplier probe completes first,
device_links_driver_bound() called for it will skip the link state
update and when it is called for the consumer, the link state will
be updated to "active".  In turn, if the consumer probe completes
first, device_links_driver_bound() called for it will change the
state of the link to "active" and when it is called for the
supplier, the link status update will be skipped.

However, in principle the supplier or consumer probe may still fail
after the link has been added, so modify device_links_no_driver() to
change device links in the "active" or "consumer probe" state to
"dormant" on the supplier side and update __device_links_no_driver()
to change the link state to "available" only if it is "consumer
probe" or "active".

Then, if the supplier probe fails first, the leftover link to the
probing consumer will become "dormant" and device_links_no_driver()
called for the consumer (when its probe fails) will clean it up.
In turn, if the consumer probe fails first, it will either drop the
link, or change its state to "available" and, in the latter case,
when device_links_no_driver() is called for the supplier, it will
update the link state to "dormant".  [If the supplier probe fails,
but the consumer probe succeeds, which should not happen as long as
the consumer driver is correct, the link still will be around, but
it will be "dormant" until the supplier is probed again.]

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
e2f3cd831a driver core: Fix handling of runtime PM flags in device_link_add()
After commit ead18c23c2 ("driver core: Introduce device links
reference counting"), if there is a link between the given supplier
and the given consumer already, device_link_add() will refcount it
and return it unconditionally without updating its flags.  It is
possible, however, that the second (or any subsequent) caller of
device_link_add() for the same consumer-supplier pair will pass
DL_FLAG_PM_RUNTIME, possibly along with DL_FLAG_RPM_ACTIVE, in flags
to it and the existing link may not behave as expected then.

First, if DL_FLAG_PM_RUNTIME is not set in the existing link's flags
at all, it needs to be set like during the original initialization of
the link.

Second, if DL_FLAG_RPM_ACTIVE is passed to device_link_add() in flags
(in addition to DL_FLAG_PM_RUNTIME), the existing link should to be
updated to reflect the "active" runtime PM configuration of the
consumer-supplier pair and extra care must be taken here to avoid
possible destructive races with runtime PM of the consumer.

To that end, redefine the rpm_active field in struct device_link
as a refcount, initialize it to 1 and make rpm_resume() (for the
consumer) and device_link_add() increment it whenever they acquire
a runtime PM reference on the supplier device.  Accordingly, make
rpm_suspend() (for the consumer) and pm_runtime_clean_up_links()
decrement it and drop runtime PM references to the supplier
device in a loop until rpm_active becones 1 again.

Fixes: ead18c23c2 ("driver core: Introduce device links reference counting")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
5db25c9eb8 driver core: Do not resume suppliers under device_links_write_lock()
It is incorrect to call pm_runtime_get_sync() under
device_links_write_lock(), because it may end up trying to take
device_links_read_lock() while resuming the target device and that
will deadlock in the non-SRCU case, so avoid that by resuming the
supplier device in device_link_add() before calling
device_links_write_lock().

Fixes: 21d5c57b37 ("PM / runtime: Use device links")
Fixes: baa8809f60 ("PM / runtime: Optimize the use of device links")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
f265df550a driver core: Avoid careless re-use of existing device links
After commit ead18c23c2 ("driver core: Introduce device links
reference counting"), if there is a link between the given supplier
and the given consumer already, device_link_add() will refcount it
and return it unconditionally.  However, if the flags passed to
it on the second (or any subsequent) attempt to create a device
link between the same consumer-supplier pair are not compatible with
the existing link's flags, that is incorrect.

First off, if the existing link is stateless and the next caller of
device_link_add() for the same consumer-supplier pair wants a
stateful one, or the other way around, the existing link cannot be
returned, because it will not match the expected behavior, so make
device_link_add() dump the stack and return NULL in that case.

Moreover, if the DL_FLAG_AUTOREMOVE_CONSUMER flag is passed to
device_link_add(), its caller will expect its reference to the link
to be dropped automatically on consumer driver removal, which will
not happen if that flag is not set in the link's flags (and
analogously for DL_FLAG_AUTOREMOVE_SUPPLIER).  For this reason, make
device_link_add() update the existing link's flags accordingly
before returning it to the caller.

Fixes: ead18c23c2 ("driver core: Introduce device links reference counting")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Rafael J. Wysocki
c8d50986da driver core: Fix DL_FLAG_AUTOREMOVE_SUPPLIER device link flag handling
Change the list walk in device_links_driver_cleanup() to a safe one
to avoid use-after-free when dropping a link from the list during the
walk.

Also, while at it, fix device_link_add() to refuse to create
stateless device links with DL_FLAG_AUTOREMOVE_SUPPLIER set, which is
an invalid combination (setting that flag means that the driver core
should manage the link, so it cannot be stateless), and extend the
kerneldoc comment of device_link_add() to cover the
DL_FLAG_AUTOREMOVE_SUPPLIER flag properly too.

Fixes: 1689cac5b3 ("driver core: Add flag to autoremove device link on supplier unbind")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Alexander Duyck
3451a495ef driver core: Establish order of operations for device_add and device_del via bitflag
Add an additional bit flag to the device_private struct named "dead".

This additional flag provides a guarantee that when a device_del is
executed on a given interface an async worker will not attempt to attach
the driver following the earlier device_del call. Previously this
guarantee was not present and could result in the device_del call
attempting to remove a driver from an interface only to have the async
worker attempt to probe the driver later when it finally completes the
asynchronous probe call.

One additional change added was that I pulled the check for dev->driver
out of the __device_attach_driver call and instead placed it in the
__device_attach_async_helper call. This was motivated by the fact that the
only other caller of this, __device_attach, had already taken the
device_lock() and checked for dev->driver. Instead of testing for this
twice in this path it makes more sense to just consolidate the dev->dead
and dev->driver checks together into one set of checks.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 14:20:53 +01:00