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, 74 insertions, 0 deletions

diff --git a/include/scsi/scsi_status.h b/include/scsi/scsi_status.h
new file mode 100644
index 000000000..9cb85262d
--- /dev/null
+++ b/include/scsi/scsi_status.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _SCSI_SCSI_STATUS_H
+#define _SCSI_SCSI_STATUS_H
+
+#include <linux/types.h>
+#include <scsi/scsi_proto.h>
+
+/* Message codes. */
+enum scsi_msg_byte {
+	COMMAND_COMPLETE	= 0x00,
+	EXTENDED_MESSAGE	= 0x01,
+	SAVE_POINTERS		= 0x02,
+	RESTORE_POINTERS	= 0x03,
+	DISCONNECT		= 0x04,
+	INITIATOR_ERROR		= 0x05,
+	ABORT_TASK_SET		= 0x06,
+	MESSAGE_REJECT		= 0x07,
+	NOP			= 0x08,
+	MSG_PARITY_ERROR	= 0x09,
+	LINKED_CMD_COMPLETE	= 0x0a,
+	LINKED_FLG_CMD_COMPLETE	= 0x0b,
+	TARGET_RESET		= 0x0c,
+	ABORT_TASK		= 0x0d,
+	CLEAR_TASK_SET		= 0x0e,
+	INITIATE_RECOVERY	= 0x0f,            /* SCSI-II only */
+	RELEASE_RECOVERY	= 0x10,            /* SCSI-II only */
+	TERMINATE_IO_PROC	= 0x11,            /* SCSI-II only */
+	CLEAR_ACA		= 0x16,
+	LOGICAL_UNIT_RESET	= 0x17,
+	SIMPLE_QUEUE_TAG	= 0x20,
+	HEAD_OF_QUEUE_TAG	= 0x21,
+	ORDERED_QUEUE_TAG	= 0x22,
+	IGNORE_WIDE_RESIDUE	= 0x23,
+	ACA			= 0x24,
+	QAS_REQUEST		= 0x55,
+
+	/* Old SCSI2 names, don't use in new code */
+	BUS_DEVICE_RESET	= TARGET_RESET,
+	ABORT			= ABORT_TASK_SET,
+};
+
+/* Host byte codes. */
+enum scsi_host_status {
+	DID_OK		= 0x00,	/* NO error                                */
+	DID_NO_CONNECT	= 0x01,	/* Couldn't connect before timeout period  */
+	DID_BUS_BUSY	= 0x02,	/* BUS stayed busy through time out period */
+	DID_TIME_OUT	= 0x03,	/* TIMED OUT for other reason              */
+	DID_BAD_TARGET	= 0x04,	/* BAD target.                             */
+	DID_ABORT	= 0x05,	/* Told to abort for some other reason     */
+	DID_PARITY	= 0x06,	/* Parity error                            */
+	DID_ERROR	= 0x07,	/* Internal error                          */
+	DID_RESET	= 0x08,	/* Reset by somebody.                      */
+	DID_BAD_INTR	= 0x09,	/* Got an interrupt we weren't expecting.  */
+	DID_PASSTHROUGH	= 0x0a,	/* Force command past mid-layer            */
+	DID_SOFT_ERROR	= 0x0b,	/* The low level driver just wish a retry  */
+	DID_IMM_RETRY	= 0x0c,	/* Retry without decrementing retry count  */
+	DID_REQUEUE	= 0x0d,	/* Requeue command (no immediate retry) also
+				 * without decrementing the retry count	   */
+	DID_TRANSPORT_DISRUPTED = 0x0e, /* Transport error disrupted execution
+					 * and the driver blocked the port to
+					 * recover the link. Transport class will
+					 * retry or fail IO */
+	DID_TRANSPORT_FAILFAST = 0x0f, /* Transport class fastfailed the io */
+	/*
+	 * We used to have DID_TARGET_FAILURE, DID_NEXUS_FAILURE,
+	 * DID_ALLOC_FAILURE and DID_MEDIUM_ERROR at 0x10 - 0x13. For compat
+	 * with userspace apps that parse the host byte for SG IO, we leave
+	 * that block of codes unused and start at 0x14 below.
+	 */
+	DID_TRANSPORT_MARGINAL = 0x14, /* Transport marginal errors */
+};
+
+#endif /* _SCSI_SCSI_STATUS_H */