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, 45 insertions, 0 deletions

diff --git a/drivers/most/Kconfig b/drivers/most/Kconfig
new file mode 100644
index 000000000..69c9e728b
--- /dev/null
+++ b/drivers/most/Kconfig
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: GPL-2.0
+menuconfig MOST
+	tristate "MOST (Media Oriented Systems Transport) support"
+	depends on HAS_DMA && CONFIGFS_FS
+	default n
+	help
+	  Say Y here if you want to enable MOST support.
+	  This driver needs at least one additional component to enable the
+	  desired access from userspace (e.g. character devices) and one that
+	  matches the network controller's hardware interface (e.g. USB).
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called most_core.
+
+	  If in doubt, say N here.
+
+if MOST
+config MOST_USB_HDM
+	tristate "USB"
+	depends on USB
+	help
+	  Say Y here if you want to connect via USB to network transceiver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called most_usb.
+
+config MOST_CDEV
+	tristate "Cdev"
+
+	help
+	  Say Y here if you want to commumicate via character devices.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called most_cdev.
+
+config MOST_SND
+	tristate "Sound"
+	depends on SND
+	select SND_PCM
+	help
+	  Say Y here if you want to commumicate via ALSA/sound devices.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called most_sound.
+endif