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, 20 insertions, 0 deletions

diff --git a/Documentation/admin-guide/media/raspberrypi-pisp-be.dot b/Documentation/admin-guide/media/raspberrypi-pisp-be.dot
new file mode 100644
index 000000000..55671dc1d
--- /dev/null
+++ b/Documentation/admin-guide/media/raspberrypi-pisp-be.dot
@@ -0,0 +1,20 @@
+digraph board {
+	rankdir=TB
+	n00000001 [label="{{<port0> 0 | <port1> 1 | <port2> 2 | <port7> 7} | pispbe\n | {<port3> 3 | <port4> 4 | <port5> 5 | <port6> 6}}", shape=Mrecord, style=filled, fillcolor=green]
+	n00000001:port3 -> n0000001c [style=bold]
+	n00000001:port4 -> n00000022 [style=bold]
+	n00000001:port5 -> n00000028 [style=bold]
+	n00000001:port6 -> n0000002e [style=bold]
+	n0000000a [label="pispbe-input\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
+	n0000000a -> n00000001:port0 [style=bold]
+	n00000010 [label="pispbe-tdn_input\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
+	n00000010 -> n00000001:port1 [style=bold]
+	n00000016 [label="pispbe-stitch_input\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
+	n00000016 -> n00000001:port2 [style=bold]
+	n0000001c [label="pispbe-output0\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
+	n00000022 [label="pispbe-output1\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
+	n00000028 [label="pispbe-tdn_output\n/dev/video5", shape=box, style=filled, fillcolor=yellow]
+	n0000002e [label="pispbe-stitch_output\n/dev/video6", shape=box, style=filled, fillcolor=yellow]
+	n00000034 [label="pispbe-config\n/dev/video7", shape=box, style=filled, fillcolor=yellow]
+	n00000034 -> n00000001:port7 [style=bold]
+}