linux-sg2042/include
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
..
acpi Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 17:03:51 -08:00
asm-generic Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
clocksource
crypto crypto: skcipher - remove remnants of internal IV generators 2018-12-23 11:52:45 +08:00
drm Merge tag 'drm-intel-fixes-2019-01-11' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes 2019-01-11 10:26:21 +01:00
dt-bindings Merge branch 'next/drivers' into next/late 2019-01-04 14:31:38 -08:00
keys
kvm KVM: arm/arm64: Remove arch timer workqueue 2018-12-19 17:47:07 +00:00
linux driver core: Fix handling of runtime PM flags in device_link_add() 2019-02-01 10:04:08 +01:00
math-emu
media media fixes for v4.20-rc8 2018-12-25 13:11:30 -08:00
memory
misc
net Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
pcmcia
ras
rdma IB/core: uverbs copy to struct or zero helper 2018-12-20 15:18:18 -07:00
scsi 4.21 merge window pull request 2018-12-28 14:57:10 -08:00
soc ARM: SoC driver updates 2018-12-31 17:32:35 -08:00
sound ALSA: HD-Audio: SKL+: force HDaudio legacy or SKL+ driver selection 2018-12-19 18:07:23 +01:00
target scsi: target: consistently null-terminate t10_wwn strings 2018-12-07 21:54:33 -05:00
trace NFS client updates for Linux 4.21 2019-01-02 16:35:23 -08:00
uapi Fix a handful of audit-related issue 2019-01-07 08:45:47 -08:00
video drm/exynos: fimd: Make pixel blend mode configurable 2018-12-14 15:46:15 +09:00
xen xen: Introduce shared buffer helpers for page directory... 2018-12-18 12:15:55 -05:00