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, 26 insertions, 0 deletions

diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst
new file mode 100644
index 000000000..4f980815e
--- /dev/null
+++ b/Documentation/rust/arch-support.rst
@@ -0,0 +1,26 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Arch Support
+============
+
+Currently, the Rust compiler (``rustc``) uses LLVM for code generation,
+which limits the supported architectures that can be targeted. In addition,
+support for building the kernel with LLVM/Clang varies (please see
+Documentation/kbuild/llvm.rst). This support is needed for ``bindgen``
+which uses ``libclang``.
+
+Below is a general summary of architectures that currently work. Level of
+support corresponds to ``S`` values in the ``MAINTAINERS`` file.
+
+=============  ================  ==============================================
+Architecture   Level of support  Constraints
+=============  ================  ==============================================
+``arm``        Maintained        ARMv7 Little Endian only.
+``arm64``      Maintained        Little Endian only.
+``loongarch``  Maintained        \-
+``riscv``      Maintained        ``riscv64`` and LLVM/Clang only.
+``s390``       Maintained        ``CONFIG_EXPOLINE`` must be disabled.
+``um``         Maintained        \-
+``x86``        Maintained        ``x86_64`` only.
+=============  ================  ==============================================
+