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, 84 insertions, 0 deletions

diff --git a/drivers/scsi/sd_trace.h b/drivers/scsi/sd_trace.h
new file mode 100644
index 000000000..cba3c0b82
--- /dev/null
+++ b/drivers/scsi/sd_trace.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022 Western Digital Corporation or its affiliates.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sd
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE sd_trace
+
+#if !defined(_SD_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(scsi_prepare_zone_append,
+
+	    TP_PROTO(struct scsi_cmnd *cmnd, sector_t lba,
+		     unsigned int wp_offset),
+
+	    TP_ARGS(cmnd, lba, wp_offset),
+
+	    TP_STRUCT__entry(
+		     __field( unsigned int, host_no )
+		     __field( unsigned int, channel )
+		     __field( unsigned int, id )
+		     __field( unsigned int, lun )
+		     __field( sector_t,     lba )
+		     __field( unsigned int, wp_offset )
+	    ),
+
+	    TP_fast_assign(
+		__entry->host_no	= cmnd->device->host->host_no;
+		__entry->channel	= cmnd->device->channel;
+		__entry->id		= cmnd->device->id;
+		__entry->lun		= cmnd->device->lun;
+		__entry->lba		= lba;
+		__entry->wp_offset	= wp_offset;
+	    ),
+
+	    TP_printk("host_no=%u, channel=%u id=%u lun=%u lba=%llu wp_offset=%u",
+		      __entry->host_no, __entry->channel, __entry->id,
+		      __entry->lun, __entry->lba, __entry->wp_offset)
+);
+
+TRACE_EVENT(scsi_zone_wp_update,
+
+	    TP_PROTO(struct scsi_cmnd *cmnd, sector_t rq_sector,
+		     unsigned int wp_offset, unsigned int good_bytes),
+
+	    TP_ARGS(cmnd, rq_sector, wp_offset, good_bytes),
+
+	    TP_STRUCT__entry(
+		     __field( unsigned int, host_no )
+		     __field( unsigned int, channel )
+		     __field( unsigned int, id )
+		     __field( unsigned int, lun )
+		     __field( sector_t,     rq_sector )
+		     __field( unsigned int, wp_offset )
+		     __field( unsigned int, good_bytes )
+	    ),
+
+	    TP_fast_assign(
+		__entry->host_no	= cmnd->device->host->host_no;
+		__entry->channel	= cmnd->device->channel;
+		__entry->id		= cmnd->device->id;
+		__entry->lun		= cmnd->device->lun;
+		__entry->rq_sector	= rq_sector;
+		__entry->wp_offset	= wp_offset;
+		__entry->good_bytes	= good_bytes;
+	    ),
+
+	    TP_printk("host_no=%u, channel=%u id=%u lun=%u rq_sector=%llu" \
+		      " wp_offset=%u good_bytes=%u",
+		      __entry->host_no, __entry->channel, __entry->id,
+		      __entry->lun, __entry->rq_sector, __entry->wp_offset,
+		      __entry->good_bytes)
+);
+#endif /* _SD_TRACE_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../drivers/scsi
+#include <trace/define_trace.h>