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, 69 insertions, 0 deletions

diff --git a/include/scsi/sas_ata.h b/include/scsi/sas_ata.h
new file mode 100644
index 000000000..a161c0222
--- /dev/null
+++ b/include/scsi/sas_ata.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Support for SATA devices on Serial Attached SCSI (SAS) controllers
+ *
+ * Copyright (C) 2006 IBM Corporation
+ *
+ * Written by: Darrick J. Wong <djwong@us.ibm.com>, IBM Corporation
+ */
+
+#ifndef _SAS_ATA_H_
+#define _SAS_ATA_H_
+
+#include <linux/libata.h>
+#include <scsi/libsas.h>
+
+#ifdef CONFIG_SCSI_SAS_ATA
+
+static inline bool dev_is_sata(struct domain_device *dev)
+{
+	switch (dev->dev_type) {
+	case SAS_SATA_DEV:
+	case SAS_SATA_PENDING:
+	case SAS_SATA_PM:
+	case SAS_SATA_PM_PORT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+void sas_ata_schedule_reset(struct domain_device *dev);
+void sas_ata_device_link_abort(struct domain_device *dev, bool force_reset);
+int sas_execute_ata_cmd(struct domain_device *device, u8 *fis, int force_phy_id);
+int smp_ata_check_ready_type(struct ata_link *link);
+
+extern const struct attribute_group sas_ata_sdev_attr_group;
+
+#else
+
+static inline bool dev_is_sata(struct domain_device *dev)
+{
+	return false;
+}
+
+static inline void sas_ata_schedule_reset(struct domain_device *dev)
+{
+}
+
+static inline void sas_ata_device_link_abort(struct domain_device *dev,
+					     bool force_reset)
+{
+}
+
+static inline int sas_execute_ata_cmd(struct domain_device *device, u8 *fis,
+				      int force_phy_id)
+{
+	return 0;
+}
+
+static inline int smp_ata_check_ready_type(struct ata_link *link)
+{
+	return 0;
+}
+
+#define sas_ata_sdev_attr_group ((struct attribute_group) {})
+
+#endif
+
+#endif /* _SAS_ATA_H_ */