linux-stable.git/drivers/base/power, branch v5.4.78

PM: runtime: Drop pm_runtime_clean_up_links()

2020-11-10T11:37:34+00:00

commit d6e36668598154820177bfd78c1621d8e6c580a2 upstream.

After commit d12544fb2aa9 ("PM: runtime: Remove link state checks in
rpm_get/put_supplier()") nothing prevents the consumer device's
runtime PM from acquiring additional references to the supplier
device after pm_runtime_clean_up_links() has run (or even while it
is running), so calling this function from __device_release_driver()
may be pointless (or even harmful).

Moreover, it ignores stateless device links, so the runtime PM
handling of managed and stateless device links is inconsistent
because of it, so better get rid of it entirely.

Fixes: d12544fb2aa9 ("PM: runtime: Remove link state checks in rpm_get/put_supplier()")
Signed-off-by: Rafael J. Wysocki 
Cc: 5.1+  # 5.1+
Tested-by: Xiang Chen 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

PM: runtime: Drop runtime PM references to supplier on link removal

2020-11-10T11:37:34+00:00

commit e0e398e204634db8fb71bd89cf2f6e3e5bd09b51 upstream.

While removing a device link, drop the supplier device's runtime PM
usage counter as many times as needed to drop all of the runtime PM
references to it from the consumer in addition to dropping the
consumer's link count.

Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links")
Signed-off-by: Rafael J. Wysocki 
Cc: 5.1+  # 5.1+
Tested-by: Xiang Chen 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

PM: runtime: Remove link state checks in rpm_get/put_supplier()

2020-11-05T10:43:26+00:00

commit d12544fb2aa9944b180c35914031a8384ab082c1 upstream.

To support runtime PM for hisi SAS driver (the driver is in directory
drivers/scsi/hisi_sas), we add device link between scsi_device->sdev_gendev
(consumer device) and hisi_hba->dev(supplier device) with flags
DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE.

After runtime suspended consumers and supplier, unload the dirver which
causes a hung.

We found that it called function device_release_driver_internal() to
release the supplier device (hisi_hba->dev), as the device link was
busy, it set the device link state to DL_STATE_SUPPLIER_UNBIND, and
then it called device_release_driver_internal() to release the consumer
device (scsi_device->sdev_gendev).

Then it would try to call pm_runtime_get_sync() to resume the consumer
device, but because consumer-supplier relation existed, it would try
to resume the supplier first, but as the link state was already
DL_STATE_SUPPLIER_UNBIND, so it skipped resuming the supplier and only
resumed the consumer which hanged (it sends IOs to resume scsi_device
while the SAS controller is suspended).

Simple flow is as follows:

device_release_driver_internal -> (supplier device)
    if device_links_busy ->
	device_links_unbind_consumers ->
	    ...
	    WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND)
	    device_release_driver_internal (consumer device)
    pm_runtime_get_sync -> (consumer device)
	...
	__rpm_callback ->
	    rpm_get_suppliers ->
		if link->state == DL_STATE_SUPPLIER_UNBIND -> skip the action of resuming the supplier
		...
    pm_runtime_clean_up_links
    ...

Correct suspend/resume ordering between a supplier device and its consumer
devices (resume the supplier device before resuming consumer devices, and
suspend consumer devices before suspending the supplier device) should be
guaranteed by runtime PM, but the state checks in rpm_get_supplier() and
rpm_put_supplier() break this rule, so remove them.

Signed-off-by: Xiang Chen 
[ rjw: Subject and changelog edits ]
Cc: All applicable 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM: sleep: core: Fix the handling of pending runtime resume requests

2020-09-03T09:27:05+00:00

commit e3eb6e8fba65094328b8dca635d00de74ba75b45 upstream.

It has been reported that system-wide suspend may be aborted in the
absence of any wakeup events due to unforseen interactions of it with
the runtume PM framework.

One failing scenario is when there are multiple devices sharing an
ACPI power resource and runtime-resume needs to be carried out for
one of them during system-wide suspend (for example, because it needs
to be reconfigured before the whole system goes to sleep).  In that
case, the runtime-resume of that device involves turning the ACPI
power resource "on" which in turn causes runtime-resume requests
to be queued up for all of the other devices sharing it.  Those
requests go to the runtime PM workqueue which is frozen during
system-wide suspend, so they are not actually taken care of until
the resume of the whole system, but the pm_runtime_barrier()
call in __device_suspend() sees them and triggers system wakeup
events for them which then cause the system-wide suspend to be
aborted if wakeup source objects are in active use.

Of course, the logic that leads to triggering those wakeup events is
questionable in the first place, because clearly there are cases in
which a pending runtime resume request for a device is not connected
to any real wakeup events in any way (like the one above).  Moreover,
it is racy, because the device may be resuming already by the time
the pm_runtime_barrier() runs and so if the driver doesn't take care
of signaling the wakeup event as appropriate, it will be lost.
However, if the driver does take care of that, the extra
pm_wakeup_event() call in the core is redundant.

Accordingly, drop the conditional pm_wakeup_event() call fron
__device_suspend() and make the latter call pm_runtime_barrier()
alone.  Also modify the comment next to that call to reflect the new
code and extend it to mention the need to avoid unwanted interactions
between runtime PM and system-wide device suspend callbacks.

Fixes: 1e2ef05bb8cf8 ("PM: Limit race conditions between runtime PM and system sleep (v2)")
Signed-off-by: Rafael J. Wysocki 
Acked-by: Alan Stern 
Reported-by: Utkarsh H Patel 
Tested-by: Utkarsh H Patel 
Tested-by: Pengfei Xu 
Cc: All applicable 
Signed-off-by: Greg Kroah-Hartman

PM: wakeup: Show statistics for deleted wakeup sources again

2020-07-31T16:39:32+00:00

commit e976eb4b91e906f20ec25b20c152d53c472fc3fd upstream.

After commit 00ee22c28915 (PM / wakeup: Use seq_open() to show wakeup
stats), print_wakeup_source_stats(m, &deleted_ws) is not called from
wakeup_sources_stats_seq_show() any more.

Because deleted_ws is one of the wakeup sources, it should be shown
too, so add it to the end of all other wakeup sources.

Signed-off-by: zhuguangqing 
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Florian Fainelli 
Signed-off-by: Greg Kroah-Hartman

PM: sleep: core: Switch back to async_schedule_dev()

2020-05-02T06:48:53+00:00

commit 09beebd8f93b3c8bf894e342f0a203a5c612478c upstream.

Commit 8b9ec6b73277 ("PM core: Use new async_schedule_dev command")
introduced a new function for better performance.

However commit f2a424f6c613 ("PM / core: Introduce dpm_async_fn()
helper") went back to the non-optimized version, async_schedule().

So switch back to the sync_schedule_dev() to improve performance

Fixes: f2a424f6c613 ("PM / core: Introduce dpm_async_fn() helper")
Signed-off-by: Kai-Heng Feng 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM: sleep: wakeup: Skip wakeup_source_sysfs_remove() if device is not there

2020-04-17T08:50:12+00:00

commit 87de6594dc45dbf6819f3e0ef92f9331c5a9444c upstream.

Skip wakeup_source_sysfs_remove() to fix a NULL pinter dereference via
ws->dev, if the wakeup source is unregistered before registering the
wakeup class from device_add().

Fixes: 2ca3d1ecb8c4 ("PM / wakeup: Register wakeup class kobj after device is added")
Signed-off-by: Neeraj Upadhyay 
Cc: 5.4+  # 5.4+
[ rjw: Subject & changelog, white space ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM / Domains: Allow no domain-idle-states DT property in genpd when parsing

2020-04-17T08:50:12+00:00

commit 56cb26891ea4180121265dc6b596015772c4a4b8 upstream.

Commit 2c361684803e ("PM / Domains: Don't treat zero found compatible idle
states as an error"), moved of_genpd_parse_idle_states() towards allowing
none compatible idle state to be found for the device node, rather than
returning an error code.

However, it didn't consider that the "domain-idle-states" DT property may
be missing as it's optional, which makes of_count_phandle_with_args() to
return -ENOENT. Let's fix this to make the behaviour consistent.

Fixes: 2c361684803e ("PM / Domains: Don't treat zero found compatible idle states as an error")
Reported-by: Benjamin Gaignard 
Cc: 4.20+  # 4.20+
Reviewed-by: Sudeep Holla 
Signed-off-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM: core: Fix handling of devices deleted during system-wide resume

2020-02-11T12:35:25+00:00

commit 0552e05fdfea191a2cf3a0abd33574b5ef9ca818 upstream.

If a device is deleted by one of its system-wide resume callbacks
(for example, because it does not appear to be present or accessible
any more) along with its children, the resume of the children may
continue leading to use-after-free errors and other issues
(potentially).

Namely, if the device's children are resumed asynchronously, their
resume may have been scheduled already before the device's callback
runs and so the device may be deleted while dpm_wait_for_superior()
is being executed for them.  The memory taken up by the parent device
object may be freed then while dpm_wait() is waiting for the parent's
resume callback to complete, which leads to a use-after-free.
Moreover, the resume of the children is really not expected to
continue after they have been unregistered, so it must be terminated
right away in that case.

To address this problem, modify dpm_wait_for_superior() to check
if the target device is still there in the system-wide PM list of
devices and if so, to increment its parent's reference counter, both
under dpm_list_mtx which prevents device_del() running for the child
from dropping the parent's reference counter prematurely.

If the device is not present in the system-wide PM list of devices
any more, the resume of it cannot continue, so check that again after
dpm_wait() returns, which means that the parent's callback has been
completed, and pass the result of that check to the caller of
dpm_wait_for_superior() to allow it to abort the device's resume
if it is not there any more.

Link: https://lore.kernel.org/linux-pm/1579568452-27253-1-git-send-email-chanho.min@lge.com
Reported-by: Chanho Min 
Cc: All applicable 
Signed-off-by: Rafael J. Wysocki 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

PM: QoS: Drop frequency QoS types from device PM QoS

2019-10-21T00:05:21+00:00

There are no more active users of DEV_PM_QOS_MIN_FREQUENCY and
DEV_PM_QOS_MAX_FREQUENCY device PM QoS request types, so drop them
along with the code supporting them.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar