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, 73 insertions, 0 deletions

diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
new file mode 100644
index 000000000..8402b0c93
--- /dev/null
+++ b/rust/bindgen_parameters
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# We want to map these types to `isize`/`usize` manually, instead of
+# define them as `int`/`long` depending on platform bitwidth.
+--blocklist-type __kernel_s?size_t
+--blocklist-type __kernel_ptrdiff_t
+
+--opaque-type xregs_state
+--opaque-type desc_struct
+--opaque-type arch_lbr_state
+--opaque-type local_apic
+
+# Packed type cannot transitively contain a `#[repr(align)]` type.
+--opaque-type alt_instr
+--opaque-type x86_msi_data
+--opaque-type x86_msi_addr_lo
+# s390-only: same packed/align issue as above (E0588).
+--opaque-type lowcore
+--opaque-type tod_clock
+--opaque-type tpi_info
+--opaque-type uv_cb.*
+--opaque-type uv_secret.*
+--opaque-type zpci_fib
+
+# If SMP is disabled, `arch_spinlock_t` is defined as a ZST which triggers a Rust
+# warning. We don't need to peek into it anyway.
+--opaque-type spinlock
+
+# enums that appear in indirect function calls should specify a cfi type
+--newtype-enum lru_status
+--with-attribute-custom-enum=lru_status='#[cfi_encoding="10lru_status"]'
+
+# `seccomp`'s comment gets understood as a doctest
+--no-doc-comments
+
+# These functions use the `__preserve_most` calling convention, which neither bindgen
+# nor Rust currently understand, and which Clang currently declares to be unstable.
+--blocklist-function __list_.*_report
+
+# These constants are sometimes not recognized by bindgen depending on config.
+# We use const helpers to aid bindgen, to avoid conflicts when constants are
+# recognized, block generation of the non-helper constants.
+--blocklist-item ARCH_SLAB_MINALIGN
+--blocklist-item ARCH_KMALLOC_MINALIGN
+--blocklist-item VM_MERGEABLE
+--blocklist-item VM_READ
+--blocklist-item VM_WRITE
+--blocklist-item VM_EXEC
+--blocklist-item VM_SHARED
+--blocklist-item VM_MAYREAD
+--blocklist-item VM_MAYWRITE
+--blocklist-item VM_MAYEXEC
+--blocklist-item VM_MAYEXEC
+--blocklist-item VM_PFNMAP
+--blocklist-item VM_IO
+--blocklist-item VM_DONTCOPY
+--blocklist-item VM_DONTEXPAND
+--blocklist-item VM_LOCKONFAULT
+--blocklist-item VM_ACCOUNT
+--blocklist-item VM_NORESERVE
+--blocklist-item VM_HUGETLB
+--blocklist-item VM_SYNC
+--blocklist-item VM_ARCH_1
+--blocklist-item VM_WIPEONFORK
+--blocklist-item VM_DONTDUMP
+--blocklist-item VM_SOFTDIRTY
+--blocklist-item VM_MIXEDMAP
+--blocklist-item VM_HUGEPAGE
+--blocklist-item VM_NOHUGEPAGE
+
+# Structs should implement `Zeroable` when all of their fields do.
+--with-derive-custom-struct .*=MaybeZeroable
+--with-derive-custom-union .*=MaybeZeroable