x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 96 insertions, 0 deletions

diff --git a/drivers/powercap/Kconfig b/drivers/powercap/Kconfig
new file mode 100644
index 000000000..03c4c796d
--- /dev/null
+++ b/drivers/powercap/Kconfig
@@ -0,0 +1,96 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Generic power capping sysfs interface configuration
+#
+
+menuconfig POWERCAP
+	bool "Generic powercap sysfs driver"
+	help
+	  The power capping sysfs interface allows kernel subsystems to expose power
+	  capping settings to user space in a consistent way.  Usually, it consists
+	  of multiple control types that determine which settings may be exposed and
+	  power zones representing parts of the system that can be subject to power
+	  capping.
+
+	  If you want this code to be compiled in, say Y here.
+
+if POWERCAP
+# Client driver configurations go here.
+config INTEL_RAPL_CORE
+	tristate
+	depends on PCI
+	select IOSF_MBI
+
+config INTEL_RAPL
+	tristate "Intel RAPL Support via MSR Interface"
+	depends on X86 && PCI
+	select INTEL_RAPL_CORE
+	help
+	  This enables support for the Intel Running Average Power Limit (RAPL)
+	  technology via MSR interface, which allows power limits to be enforced
+	  and monitored on modern Intel processors (Sandy Bridge and later).
+
+	  In RAPL, the platform level settings are divided into domains for
+	  fine grained control. These domains include processor package, DRAM
+	  controller, CPU core (Power Plane 0), graphics uncore (Power Plane
+	  1), etc.
+
+config INTEL_RAPL_TPMI
+	tristate "Intel RAPL Support via TPMI Interface"
+	depends on X86
+	depends on INTEL_TPMI
+	select INTEL_RAPL_CORE
+	help
+	  This enables support for the Intel Running Average Power Limit (RAPL)
+	  technology via TPMI interface, which allows power limits to be enforced
+	  and monitored.
+
+	  In RAPL, the platform level settings are divided into domains for
+	  fine grained control. These domains include processor package, DRAM
+	  controller, platform, etc.
+
+config IDLE_INJECT
+	bool "Idle injection framework"
+	depends on CPU_IDLE
+	default n
+	help
+	  This enables support for the idle injection framework. It
+	  provides a way to force idle periods on a set of specified
+	  CPUs for power capping. Idle period can be injected
+	  synchronously on a set of specified CPUs or alternatively
+	  on a per CPU basis.
+
+config ARM_SCMI_POWERCAP
+	tristate "ARM SCMI Powercap driver"
+	depends on ARM_SCMI_PROTOCOL
+	help
+	  This enables support for the ARM Powercap based on ARM SCMI
+	  Powercap protocol.
+
+	  ARM SCMI Powercap protocol allows power limits to be enforced
+	  and monitored against the SCMI Powercap domains advertised as
+	  available by the SCMI platform firmware.
+
+	  When compiled as module it will be called arm_scmi_powercap.ko.
+
+config DTPM
+	bool "Power capping for Dynamic Thermal Power Management (EXPERIMENTAL)"
+	depends on OF
+	help
+	  This enables support for the power capping for the dynamic
+	  thermal power management userspace engine.
+
+config DTPM_CPU
+	bool "Add CPU power capping based on the energy model"
+	depends on DTPM && ENERGY_MODEL && SMP
+	help
+	  This enables support for CPU power limitation based on
+	  energy model.
+
+config DTPM_DEVFREQ
+	bool "Add device power capping based on the energy model"
+	depends on DTPM && ENERGY_MODEL
+	help
+	  This enables support for device power limitation based on
+	  energy model.
+endif