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, 27 insertions, 0 deletions

diff --git a/drivers/parisc/README.dino b/drivers/parisc/README.dino
new file mode 100644
index 000000000..162742699
--- /dev/null
+++ b/drivers/parisc/README.dino
@@ -0,0 +1,27 @@
+/*
+** HP VISUALIZE Workstation PCI Bus Defect
+**
+** "HP has discovered a potential system defect that can affect
+** the behavior of five models of HP VISUALIZE workstations when
+** equipped with third-party or customer-installed PCI I/O expansion
+** cards. The defect is limited to the HP C180, C160, C160L, B160L,
+** and B132L VISUALIZE workstations, and will only be encountered
+** when data is transmitted through PCI I/O expansion cards on the
+** PCI bus. HP-supplied graphics cards that utilize the PCI bus are
+** not affected."
+**
+** http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?locale=en_US&prodTypeId=12454&prodSeriesId=44443
+**
+**	Product		First Good Serial Number
+**  C200/C240 (US)	US67350000
+**B132L+/B180 (US)	US67390000
+**   C200 (Europe)	3713G01000
+**  B180L (Europe)	3720G01000
+**
+** Note that many boards were fixed/replaced under a free replacement
+** program. Assume a machine is only "suspect" until proven otherwise.
+**
+** "The pci_check program will also be available as application
+**  patch PHSS_12295"
+*/
+