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, 62 insertions, 0 deletions

diff --git a/drivers/usb/isp1760/Kconfig b/drivers/usb/isp1760/Kconfig
new file mode 100644
index 000000000..e19178f3c
--- /dev/null
+++ b/drivers/usb/isp1760/Kconfig
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_ISP1760
+	tristate "NXP ISP 1760/1761/1763 support"
+	depends on USB || USB_GADGET
+	select REGMAP_MMIO
+	help
+	  Say Y or M here if your system as an ISP1760/1763 USB host controller
+	  or an ISP1761 USB dual-role controller.
+
+	  This driver does not support isochronous transfers or OTG.
+	  This USB controller is usually attached to a non-DMA-Master
+	  capable bus. NXP's eval kit brings this chip on PCI card
+	  where the chip itself is behind a PLB to simulate such
+	  a bus.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called isp1760.
+
+config USB_ISP1760_HCD
+	bool
+
+config USB_ISP1761_UDC
+	bool
+
+if USB_ISP1760
+
+choice
+	prompt "ISP1760 Mode Selection"
+	default USB_ISP1760_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_ISP1760_HOST_ROLE if (USB && !USB_GADGET)
+	default USB_ISP1760_GADGET_ROLE if (!USB && USB_GADGET)
+
+config USB_ISP1760_HOST_ROLE
+	bool "Host only mode"
+	depends on USB=y || USB=USB_ISP1760
+	select USB_ISP1760_HCD
+	help
+	  Select this if you want to use the ISP1760 in host mode only. The
+	  gadget function will be disabled.
+
+config USB_ISP1760_GADGET_ROLE
+	bool "Gadget only mode"
+	depends on USB_GADGET=y || USB_GADGET=USB_ISP1760
+	select USB_ISP1761_UDC
+	help
+	  Select this if you want to use the ISP1760 in peripheral mode only.
+	  The host function will be disabled.
+
+config USB_ISP1760_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on USB=y || USB=USB_ISP1760
+	depends on USB_GADGET=y || USB_GADGET=USB_ISP1760
+	select USB_ISP1760_HCD
+	select USB_ISP1761_UDC
+	help
+	  Select this if you want to use the ISP1760 in both host and
+	  peripheral modes.
+
+endchoice
+
+endif