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, 118 insertions, 0 deletions

diff --git a/drivers/bcma/Kconfig b/drivers/bcma/Kconfig
new file mode 100644
index 000000000..b9558ff20
--- /dev/null
+++ b/drivers/bcma/Kconfig
@@ -0,0 +1,118 @@
+# SPDX-License-Identifier: GPL-2.0
+config BCMA_POSSIBLE
+	bool
+	depends on HAS_IOMEM && HAS_DMA
+	default y
+
+menuconfig BCMA
+	tristate "Broadcom specific AMBA"
+	depends on BCMA_POSSIBLE
+	help
+	  Bus driver for Broadcom specific Advanced Microcontroller Bus
+	  Architecture.
+
+if BCMA
+
+# Support for Block-I/O. SELECT this from the driver that needs it.
+config BCMA_BLOCKIO
+	bool
+
+config BCMA_HOST_PCI_POSSIBLE
+	bool
+	depends on PCI = y
+	default y
+
+config BCMA_HOST_PCI
+	bool "Support for BCMA on PCI-host bus"
+	depends on BCMA_HOST_PCI_POSSIBLE
+	select BCMA_DRIVER_PCI
+	default y
+
+config BCMA_HOST_SOC
+	bool "Support for BCMA in a SoC"
+	depends on HAS_IOMEM
+	help
+	  Host interface for a Broadcom AIX bus directly mapped into
+	  the memory. This only works with the Broadcom SoCs from the
+	  BCM47XX line.
+
+	  If unsure, say N
+
+config BCMA_DRIVER_PCI
+	bool "BCMA Broadcom PCI core driver"
+	depends on PCI
+	default y
+	help
+	  BCMA bus may have many versions of PCIe core. This driver
+	  supports:
+	  1) PCIe core working in clientmode
+	  2) PCIe Gen 2 clientmode core
+
+	  In general PCIe (Gen 2) clientmode core is required on PCIe
+	  hosted buses. It's responsible for initialization and basic
+	  hardware management.
+	  This driver is also prerequisite for a hostmode PCIe core
+	  support.
+
+config BCMA_DRIVER_PCI_HOSTMODE
+	bool "Driver for PCI core working in hostmode"
+	depends on MIPS && BCMA_DRIVER_PCI && PCI_DRIVERS_LEGACY && BCMA = y
+	help
+	  PCI core hostmode operation (external PCI bus).
+
+config BCMA_DRIVER_MIPS
+	bool "BCMA Broadcom MIPS core driver"
+	depends on MIPS || COMPILE_TEST
+	help
+	  Driver for the Broadcom MIPS core attached to Broadcom specific
+	  Advanced Microcontroller Bus.
+
+	  If unsure, say N
+
+config BCMA_PFLASH
+	bool
+	depends on BCMA_DRIVER_MIPS
+	default y
+
+config BCMA_SFLASH
+	bool "ChipCommon-attached serial flash support"
+	depends on BCMA_HOST_SOC
+	default y
+	help
+	  Some cheap devices have serial flash connected to the ChipCommon
+	  instead of independent SPI controller. It requires using a separated
+	  driver that implements ChipCommon specific interface communication.
+
+	  Enabling this symbol will let bcma recognize serial flash and register
+	  it as platform device.
+
+config BCMA_NFLASH
+	bool
+	depends on BCMA_DRIVER_MIPS
+	default y
+
+config BCMA_DRIVER_GMAC_CMN
+	bool "BCMA Broadcom GBIT MAC COMMON core driver"
+	help
+	  Driver for the Broadcom GBIT MAC COMMON core attached to Broadcom
+	  specific Advanced Microcontroller Bus.
+
+	  If unsure, say N
+
+config BCMA_DRIVER_GPIO
+	bool "BCMA GPIO driver"
+	depends on GPIOLIB
+	select GPIOLIB_IRQCHIP if BCMA_HOST_SOC
+	help
+	  Driver to provide access to the GPIO pins of the bcma bus.
+
+	  If unsure, say N
+
+config BCMA_DEBUG
+	bool "BCMA debugging"
+	help
+	  This turns on additional debugging messages.
+
+	  If unsure, say N
+
+endif # BCMA