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, 48 insertions, 0 deletions

diff --git a/Documentation/driver-api/miscellaneous.rst b/Documentation/driver-api/miscellaneous.rst
new file mode 100644
index 000000000..4a5104a36
--- /dev/null
+++ b/Documentation/driver-api/miscellaneous.rst
@@ -0,0 +1,48 @@
+Parallel Port Devices
+=====================
+
+.. kernel-doc:: include/linux/parport.h
+   :internal:
+
+.. kernel-doc:: drivers/parport/ieee1284.c
+   :export:
+
+.. kernel-doc:: drivers/parport/share.c
+   :export:
+
+.. kernel-doc:: drivers/parport/daisy.c
+   :internal:
+
+16x50 UART Driver
+=================
+
+.. kernel-doc:: drivers/tty/serial/8250/8250_core.c
+   :export:
+
+See serial/driver.rst for related APIs.
+
+Pulse-Width Modulation (PWM)
+============================
+
+Pulse-width modulation is a modulation technique primarily used to
+control power supplied to electrical devices.
+
+The PWM framework provides an abstraction for providers and consumers of
+PWM signals. A controller that provides one or more PWM signals is
+registered as :c:type:`struct pwm_chip <pwm_chip>`. Providers
+are expected to embed this structure in a driver-specific structure.
+This structure contains fields that describe a particular chip.
+
+A chip exposes one or more PWM signal sources, each of which exposed as
+a :c:type:`struct pwm_device <pwm_device>`. Operations can be
+performed on PWM devices to control the period, duty cycle, polarity and
+active state of the signal.
+
+Note that PWM devices are exclusive resources: they can always only be
+used by one consumer at a time.
+
+.. kernel-doc:: include/linux/pwm.h
+   :internal:
+
+.. kernel-doc:: drivers/pwm/core.c
+   :export: