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, 60 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-fpga-manager b/Documentation/ABI/testing/sysfs-class-fpga-manager
new file mode 100644
index 000000000..d78689c35
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-fpga-manager
@@ -0,0 +1,60 @@
+What:		/sys/class/fpga_manager/<fpga>/name
+Date:		August 2015
+KernelVersion:	4.3
+Contact:	Alan Tull <atull@opensource.altera.com>
+Description:	Name of low level fpga manager driver.
+
+What:		/sys/class/fpga_manager/<fpga>/state
+Date:		August 2015
+KernelVersion:	4.3
+Contact:	Alan Tull <atull@opensource.altera.com>
+Description:	Read fpga manager state as a string.
+		The intent is to provide enough detail that if something goes
+		wrong during FPGA programming (something that the driver can't
+		fix) then userspace can know, i.e. if the firmware request
+		fails, that could be due to not being able to find the firmware
+		file.
+
+		This is a superset of FPGA states and fpga manager driver
+		states.  The fpga manager driver is walking through these steps
+		to get the FPGA into a known operating state.  It's a sequence,
+		though some steps may get skipped.  Valid FPGA states will vary
+		by manufacturer; this is a superset.
+
+		* unknown		= can't determine state
+		* power off		= FPGA power is off
+		* power up		= FPGA reports power is up
+		* reset			= FPGA held in reset state
+		* firmware request	= firmware class request in progress
+		* firmware request error = firmware request failed
+		* write init		= preparing FPGA for programming
+		* write init error	= Error while preparing FPGA for programming
+		* write			= FPGA ready to receive image data
+		* write error		= Error while programming
+		* write complete	= Doing post programming steps
+		* write complete error	= Error while doing post programming
+		* operating		= FPGA is programmed and operating
+
+What:		/sys/class/fpga_manager/<fpga>/status
+Date:		June 2018
+KernelVersion:	4.19
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read fpga manager status as a string.
+		If FPGA programming operation fails, it could be caused by crc
+		error or incompatible bitstream image. The intent of this
+		interface is to provide more detailed information for FPGA
+		programming errors to userspace. This is a list of strings for
+		the supported status.
+
+		* reconfig operation error	- invalid operations detected by
+						  reconfiguration hardware.
+						  e.g. start reconfiguration
+						  with errors not cleared
+		* reconfig CRC error		- CRC error detected by
+						  reconfiguration hardware.
+		* reconfig incompatible image	- reconfiguration image is
+						  incompatible with hardware
+		* reconfig IP protocol error	- protocol errors detected by
+						  reconfiguration hardware
+		* reconfig fifo overflow error	- FIFO overflow detected by
+						  reconfiguration hardware