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, 37 insertions, 0 deletions

diff --git a/drivers/net/mdio/Makefile b/drivers/net/mdio/Makefile
new file mode 100644
index 000000000..048586746
--- /dev/null
+++ b/drivers/net/mdio/Makefile
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for Linux MDIO bus drivers
+
+obj-$(CONFIG_ACPI_MDIO)		+= acpi_mdio.o
+obj-$(CONFIG_FWNODE_MDIO)	+= fwnode_mdio.o
+obj-$(CONFIG_OF_MDIO)		+= of_mdio.o
+
+obj-$(CONFIG_MDIO_AIROHA)		+= mdio-airoha.o
+obj-$(CONFIG_MDIO_ASPEED)		+= mdio-aspeed.o
+obj-$(CONFIG_MDIO_BCM_IPROC)		+= mdio-bcm-iproc.o
+obj-$(CONFIG_MDIO_BCM_UNIMAC)		+= mdio-bcm-unimac.o
+obj-$(CONFIG_MDIO_BITBANG)		+= mdio-bitbang.o
+obj-$(CONFIG_MDIO_CAVIUM)		+= mdio-cavium.o
+obj-$(CONFIG_MDIO_GPIO)			+= mdio-gpio.o
+obj-$(CONFIG_MDIO_HISI_FEMAC)		+= mdio-hisi-femac.o
+obj-$(CONFIG_MDIO_I2C)			+= mdio-i2c.o
+obj-$(CONFIG_MDIO_IPQ4019)		+= mdio-ipq4019.o
+obj-$(CONFIG_MDIO_IPQ8064)		+= mdio-ipq8064.o
+obj-$(CONFIG_MDIO_MOXART)		+= mdio-moxart.o
+obj-$(CONFIG_MDIO_MSCC_MIIM)		+= mdio-mscc-miim.o
+obj-$(CONFIG_MDIO_MVUSB)		+= mdio-mvusb.o
+obj-$(CONFIG_MDIO_OCTEON)		+= mdio-octeon.o
+obj-$(CONFIG_MDIO_PIC64HPSC)		+= mdio-pic64hpsc.o
+obj-$(CONFIG_MDIO_REALTEK_RTL9300)	+= mdio-realtek-rtl9300.o
+obj-$(CONFIG_MDIO_REGMAP)		+= mdio-regmap.o
+obj-$(CONFIG_MDIO_SUN4I)		+= mdio-sun4i.o
+obj-$(CONFIG_MDIO_THUNDER)		+= mdio-thunder.o
+obj-$(CONFIG_MDIO_XGENE)		+= mdio-xgene.o
+
+obj-$(CONFIG_MDIO_BUS_MUX)		+= mdio-mux.o
+obj-$(CONFIG_MDIO_BUS_MUX_BCM6368)	+= mdio-mux-bcm6368.o
+obj-$(CONFIG_MDIO_BUS_MUX_BCM_IPROC)	+= mdio-mux-bcm-iproc.o
+obj-$(CONFIG_MDIO_BUS_MUX_GPIO)		+= mdio-mux-gpio.o
+obj-$(CONFIG_MDIO_BUS_MUX_MESON_G12A)	+= mdio-mux-meson-g12a.o
+obj-$(CONFIG_MDIO_BUS_MUX_MESON_GXL)	+= mdio-mux-meson-gxl.o
+obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) 	+= mdio-mux-mmioreg.o
+obj-$(CONFIG_MDIO_BUS_MUX_MULTIPLEXER) 	+= mdio-mux-multiplexer.o