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, 64 insertions, 0 deletions

diff --git a/fs/romfs/Kconfig b/fs/romfs/Kconfig
new file mode 100644
index 000000000..f24a96a33
--- /dev/null
+++ b/fs/romfs/Kconfig
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ROMFS_FS
+	tristate "ROM file system support"
+	depends on BLOCK || MTD
+	help
+	  This is a very small read-only file system mainly intended for
+	  initial ram disks of installation disks, but it could be used for
+	  other read-only media as well.  Read
+	  <file:Documentation/filesystems/romfs.rst> for details.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called romfs.  Note that the file system of your
+	  root partition (the one containing the directory /) cannot be a
+	  module.
+
+	  If you don't know whether you need it, then you don't need it:
+	  answer N.
+
+#
+# Select the backing stores to be supported
+#
+choice
+	prompt "RomFS backing stores"
+	depends on ROMFS_FS
+	default ROMFS_BACKED_BY_BLOCK
+	help
+	  Select the backing stores to be supported.
+
+config ROMFS_BACKED_BY_BLOCK
+	bool "Block device-backed ROM file system support"
+	depends on BLOCK
+	help
+	  This permits ROMFS to use block devices buffered through the page
+	  cache as the medium from which to retrieve data.  It does not allow
+	  direct mapping of the medium.
+
+	  If unsure, answer Y.
+
+config ROMFS_BACKED_BY_MTD
+	bool "MTD-backed ROM file system support"
+	depends on MTD=y || (ROMFS_FS=m && MTD)
+	help
+	  This permits ROMFS to use MTD based devices directly, without the
+	  intercession of the block layer (which may have been disabled).  It
+	  also allows direct mapping of MTD devices through romfs files under
+	  NOMMU conditions if the underlying device is directly addressable by
+	  the CPU.
+
+	  If unsure, answer Y.
+
+config ROMFS_BACKED_BY_BOTH
+	bool "Both the above"
+	depends on BLOCK && (MTD=y || (ROMFS_FS=m && MTD))
+endchoice
+
+
+config ROMFS_ON_BLOCK
+	bool
+	default y if ROMFS_BACKED_BY_BLOCK || ROMFS_BACKED_BY_BOTH
+	select BUFFER_HEAD
+
+config ROMFS_ON_MTD
+	bool
+	default y if ROMFS_BACKED_BY_MTD || ROMFS_BACKED_BY_BOTH