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, 83 insertions, 0 deletions

diff --git a/drivers/net/pse-pd/Kconfig b/drivers/net/pse-pd/Kconfig
new file mode 100644
index 000000000..a0f2ae668
--- /dev/null
+++ b/drivers/net/pse-pd/Kconfig
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Ethernet Power Sourcing Equipment drivers
+#
+
+menuconfig PSE_CONTROLLER
+	bool "Ethernet Power Sourcing Equipment Support"
+	depends on REGULATOR
+	help
+	  Generic Power Sourcing Equipment Controller support.
+
+	  If unsure, say no.
+
+if PSE_CONTROLLER
+
+config PSE_REALTEK_MCU
+	tristate
+	help
+	  Shared core for the Realtek PSE MCU driver. This is selected
+	  automatically by the transport options below.
+
+config PSE_REALTEK_MCU_I2C
+	tristate "Realtek PSE MCU driver (I2C transport)"
+	depends on I2C
+	select PSE_REALTEK_MCU
+	help
+	  Driver for the microcontroller (MCU) that fronts the PSE
+	  hardware on various Realtek-based managed switches, attached
+	  via I2C/SMBus. The MCU exposes a message-based protocol; the actual
+	  PSE silicon is not accessed directly. To compile this driver as a
+	  module, choose M here: the module will be called realtek-pse-mcu-i2c.
+
+config PSE_REALTEK_MCU_UART
+	tristate "Realtek PSE MCU driver (UART transport)"
+	depends on SERIAL_DEV_BUS
+	select PSE_REALTEK_MCU
+	help
+	  Driver for the microcontroller (MCU) that fronts the PSE
+	  hardware on various Realtek-based managed switches, attached
+	  via UART. The MCU exposes a message-based protocol; the actual PSE
+	  silicon is not accessed directly. To compile this driver as a
+	  module, choose M here: the module will be called realtek-pse-mcu-uart.
+
+config PSE_REGULATOR
+	tristate "Regulator based PSE controller"
+	help
+	  This module provides support for simple regulator based Ethernet Power
+	  Sourcing Equipment without automatic classification support. For
+	  example for basic implementation of PoDL (802.3bu) specification.
+
+config PSE_PD692X0
+	tristate "PD692X0 PSE controller"
+	depends on I2C
+	select FW_LOADER
+	select FW_UPLOAD
+	help
+	  This module provides support for PD692x0 regulator based Ethernet
+	  Power Sourcing Equipment.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pd692x0.
+
+config PSE_SI3474
+	tristate "Si3474 PSE controller"
+	depends on I2C
+	help
+	  This module provides support for Si3474 regulator based Ethernet
+	  Power Sourcing Equipment.
+	  Only 4-pair PSE configurations are supported.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called si3474.
+
+config PSE_TPS23881
+	tristate "TPS23881 PSE controller"
+	depends on I2C
+	help
+	  This module provides support for TPS23881 regulator based Ethernet
+	  Power Sourcing Equipment.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called tps23881.
+endif