Reduce device link removal code duplication between the cases when
SRCU is enabled and when it is disabled by moving the only differing
piece of it (which is the removal of the link from the consumer and
supplier lists) into a separate wrapper function (defined differently
for each of the cases in question).

No intentional functional impact.

Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/4326215.LvFx2qVVIh@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When device_link_free() drops references to the supplier and
consumer devices of the device link going away and the reference
being dropped turns out to be the last one for any of those
device objects, its ->release callback will be invoked and it
may sleep which goes against the SRCU callback execution
requirements.

To address this issue, make the device link removal code carry out
the device_link_free() actions preceded by SRCU synchronization from
a separate work item (the "long" workqueue is used for that, because
it does not matter when the device link memory is released and it may
take time to get to that point) instead of using SRCU callbacks.

While at it, make the code work analogously when SRCU is not enabled
to reduce the differences between the SRCU and non-SRCU cases.

Fixes: 843e600b8a2b ("driver core: Fix sleeping in invalid context during device link deletion")
Cc: stable <stable@vger.kernel.org>
Reported-by: chenxiang (M) <chenxiang66@hisilicon.com>
Tested-by: chenxiang (M) <chenxiang66@hisilicon.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/5722787.lOV4Wx5bFT@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fw_devlink expects DT device nodes with "compatible" property to have
struct devices created for them. Since the connector node might not be
populated as a device, mark it as such so that fw_devlink knows not to
wait on this fwnode being populated as a struct device.

Without this patch, USB functionality can be broken on some boards.

Fixes: f7514a663016 ("of: property: fw_devlink: Add support for remote-endpoint")
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210506004423.345199-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

deferred_probe_timeout kernel commandline parameter allows probing of
consumer devices if the supplier devices don't have any drivers.

fw_devlink=on will indefintely block probe() calls on a device if all
its suppliers haven't probed successfully. This completely skips calls
to driver_deferred_probe_check_state() since that's only called when a
.probe() function calls framework APIs. So fw_devlink=on breaks
deferred_probe_timeout.

deferred_probe_timeout in its current state also ignores a lot of
information that's now available to the kernel. It assumes all suppliers
that haven't probed when the timer expires (or when initcalls are done
on a static kernel) will never probe and fails any calls to acquire
resources from these unprobed suppliers.

However, this assumption by deferred_probe_timeout isn't true under many
conditions. For example:
- If the consumer happens to be before the supplier in the deferred
  probe list.
- If the supplier itself is waiting on its supplier to probe.

This patch fixes both these issues by relaxing device links between
devices only if the supplier doesn't have any driver that could match
with (NOT bound to) the supplier device. This way, we only fail attempts
to acquire resources from suppliers that truly don't have any driver vs
suppliers that just happen to not have probed yet.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210402040342.2944858-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

remove make W=1 warning:

drivers/base/core.c:1670: warning: Function parameter or member
'flags' not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1670: warning: Function parameter or member 'con'
not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1670: warning: Function parameter or member
'sup_handle' not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1670: warning: Function parameter or member
'flags' not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1763: warning: Function parameter or member 'dev'
not described in '__fw_devlink_link_to_consumers'

drivers/base/core.c:1844: warning: Function parameter or member 'dev'
not described in '__fw_devlink_link_to_suppliers'

drivers/base/core.c:1844: warning: Function parameter or member
'fwnode' not described in '__fw_devlink_link_to_suppliers'

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210331232614.304591-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 3e4c982f1ce75faf5314477b8da296d2d00919df.

Since all reported issues due to fw_devlink=on should be addressed by
this series, revert the revert. fw_devlink=on Take II.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210302211133.2244281-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Device link status was not getting updated correctly when
device_bind_driver() is called on a device. This causes a warning[1].
Fix this by updating device links that can be updated and dropping
device links that can't be updated to a sensible state.

[1] - https://lore.kernel.org/lkml/56f7d032-ba5a-a8c7-23de-2969d98c527e@nvidia.com/

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210302211133.2244281-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull driver core / debugfs update from Greg KH:
 "Here is the "big" driver core and debugfs update for 5.12-rc1

  This set of driver core patches caused a bunch of problems in
  linux-next for the past few weeks, when Saravana tried to set
  fw_devlink=on as the default functionality. This caused a number of
  systems to stop booting, and lots of bugs were fixed in this area for
  almost all of the reported systems, but this option is not ready to be
  turned on just yet for the default operation based on this testing, so
  I've reverted that change at the very end so we don't have to worry
  about regressions in 5.12

  We will try to turn this on for 5.13 if testing goes better over the
  next few months.

  Other than the fixes caused by the fw_devlink testing in here, there's
  not much more:

   - debugfs fixes for invalid input into debugfs_lookup()

   - kerneldoc cleanups

   - warn message if platform drivers return an error on their remove
     callback (a futile effort, but good to catch).

  All of these have been in linux-next for a while now, and the
  regressions have gone away with the revert of the fw_devlink change"

* tag 'driver-core-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (35 commits)
  Revert "driver core: Set fw_devlink=on by default"
  of: property: fw_devlink: Ignore interrupts property for some configs
  debugfs: do not attempt to create a new file before the filesystem is initalized
  debugfs: be more robust at handling improper input in debugfs_lookup()
  driver core: auxiliary bus: Fix calling stage for auxiliary bus init
  of: irq: Fix the return value for of_irq_parse_one() stub
  of: irq: make a stub for of_irq_parse_one()
  clk: Mark fwnodes when their clock provider is added/removed
  PM: domains: Mark fwnodes when their powerdomain is added/removed
  irqdomain: Mark fwnodes when their irqdomain is added/removed
  driver core: fw_devlink: Handle suppliers that don't use driver core
  of: property: Add fw_devlink support for optional properties
  driver core: Add fw_devlink.strict kernel param
  of: property: Don't add links to absent suppliers
  driver core: fw_devlink: Detect supplier devices that will never be added
  driver core: platform: Emit a warning if a remove callback returned non-zero
  of: property: Fix fw_devlink handling of interrupts/interrupts-extended
  gpiolib: Don't probe gpio_device if it's not the primary device
  device.h: Remove bogus "the" in kerneldoc
  gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default
  ...

Pull MIPS updates from Thomas Bogendoerfer:

 - added support for Nintendo N64

 - added support for Realtek RTL83XX SoCs

 - kaslr support for Loongson64

 - first steps to get rid of set_fs()

 - DMA runtime coherent/non-coherent selection cleanup

 - cleanups and fixes

* tag 'mips_5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (98 commits)
  Revert "MIPS: Add basic support for ptrace single step"
  vmlinux.lds.h: catch more UBSAN symbols into .data
  MIPS: kernel: Drop kgdb_call_nmi_hook
  MAINTAINERS: Add git tree for KVM/mips
  MIPS: Use common way to parse elfcorehdr
  MIPS: Simplify EVA cache handling
  Revert "MIPS: kernel: {ftrace,kgdb}: Set correct address limit for cache flushes"
  MIPS: remove CONFIG_DMA_PERDEV_COHERENT
  MIPS: remove CONFIG_DMA_MAYBE_COHERENT
  driver core: lift dma_default_coherent into common code
  MIPS: refactor the runtime coherent vs noncoherent DMA indicators
  MIPS/alchemy: factor out the DMA coherent setup
  MIPS/malta: simplify plat_setup_iocoherency
  MIPS: Add basic support for ptrace single step
  MAINTAINERS: replace non-matching patterns for loongson{2,3}
  MIPS: Make check condition for SDBBP consistent with EJTAG spec
  mips: Replace lkml.org links with lore
  Revert "MIPS: microMIPS: Fix the judgment of mm_jr16_op and mm_jalr_op"
  MIPS: crash_dump.c: Simplify copy_oldmem_page()
  Revert "mips: Manually call fdt_init_reserved_mem() method"
  ...

This reverts commit e590474768f1cc04852190b61dec692411b22e2a.

While things are _almost_ there and working for almost all systems,
there are still reported regressions happening, so let's revert this
default for 5.12.  We can bring it back in linux-next after 5.12-rc1 is
out to get more testing and hopefully solve the remaining different
subsystem and driver issues that people are running into.

Cc: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210219074549.1506936-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>