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, 80 insertions, 0 deletions

diff --git a/include/scsi/scsi_dbg.h b/include/scsi/scsi_dbg.h
new file mode 100644
index 000000000..efcdc7853
--- /dev/null
+++ b/include/scsi/scsi_dbg.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SCSI_SCSI_DBG_H
+#define _SCSI_SCSI_DBG_H
+
+struct scsi_cmnd;
+struct scsi_device;
+struct scsi_sense_hdr;
+
+extern void scsi_print_command(struct scsi_cmnd *);
+extern size_t __scsi_format_command(char *, size_t,
+				   const unsigned char *, size_t);
+extern void scsi_print_sense_hdr(const struct scsi_device *, const char *,
+				 const struct scsi_sense_hdr *);
+extern void scsi_print_sense(struct scsi_cmnd *);
+extern void __scsi_print_sense(const struct scsi_device *, const char *name,
+			       const unsigned char *sense_buffer,
+			       int sense_len);
+extern void scsi_print_result(struct scsi_cmnd *, const char *, int);
+
+#ifdef CONFIG_SCSI_CONSTANTS
+extern bool scsi_opcode_sa_name(int, int, const char **, const char **);
+extern const char *scsi_sense_key_string(unsigned char);
+extern const char *scsi_extd_sense_format(unsigned char, unsigned char,
+					  const char **);
+extern const char *scsi_mlreturn_string(int);
+extern const char *scsi_hostbyte_string(int);
+#else
+static inline bool
+scsi_opcode_sa_name(int cmd, int sa,
+		    const char **cdb_name, const char **sa_name)
+{
+	*cdb_name = NULL;
+	switch (cmd) {
+	case VARIABLE_LENGTH_CMD:
+	case MAINTENANCE_IN:
+	case MAINTENANCE_OUT:
+	case PERSISTENT_RESERVE_IN:
+	case PERSISTENT_RESERVE_OUT:
+	case SERVICE_ACTION_IN_12:
+	case SERVICE_ACTION_OUT_12:
+	case SERVICE_ACTION_BIDIRECTIONAL:
+	case SERVICE_ACTION_IN_16:
+	case SERVICE_ACTION_OUT_16:
+	case EXTENDED_COPY:
+	case RECEIVE_COPY_RESULTS:
+		*sa_name = NULL;
+		return true;
+	default:
+		return false;
+	}
+}
+
+static inline const char *
+scsi_sense_key_string(unsigned char key)
+{
+	return NULL;
+}
+
+static inline const char *
+scsi_extd_sense_format(unsigned char asc, unsigned char ascq, const char **fmt)
+{
+	*fmt = NULL;
+	return NULL;
+}
+
+static inline const char *
+scsi_mlreturn_string(int result)
+{
+	return NULL;
+}
+
+static inline const char *
+scsi_hostbyte_string(int result)
+{
+	return NULL;
+}
+
+#endif
+
+#endif /* _SCSI_SCSI_DBG_H */