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, 66 insertions, 0 deletions

diff --git a/fs/dlm/util.c b/fs/dlm/util.c
new file mode 100644
index 000000000..f2bc401f3
--- /dev/null
+++ b/fs/dlm/util.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005-2008 Red Hat, Inc.  All rights reserved.
+**
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "rcom.h"
+#include "util.h"
+
+#define DLM_ERRNO_EDEADLK		35
+#define DLM_ERRNO_EBADR			53
+#define DLM_ERRNO_EBADSLT		57
+#define DLM_ERRNO_EPROTO		71
+#define DLM_ERRNO_EOPNOTSUPP		95
+#define DLM_ERRNO_ETIMEDOUT	       110
+#define DLM_ERRNO_EINPROGRESS	       115
+
+/* higher errno values are inconsistent across architectures, so select
+   one set of values for on the wire */
+
+int to_dlm_errno(int err)
+{
+	switch (err) {
+	case -EDEADLK:
+		return -DLM_ERRNO_EDEADLK;
+	case -EBADR:
+		return -DLM_ERRNO_EBADR;
+	case -EBADSLT:
+		return -DLM_ERRNO_EBADSLT;
+	case -EPROTO:
+		return -DLM_ERRNO_EPROTO;
+	case -EOPNOTSUPP:
+		return -DLM_ERRNO_EOPNOTSUPP;
+	case -ETIMEDOUT:
+		return -DLM_ERRNO_ETIMEDOUT;
+	case -EINPROGRESS:
+		return -DLM_ERRNO_EINPROGRESS;
+	}
+	return err;
+}
+
+int from_dlm_errno(int err)
+{
+	switch (err) {
+	case -DLM_ERRNO_EDEADLK:
+		return -EDEADLK;
+	case -DLM_ERRNO_EBADR:
+		return -EBADR;
+	case -DLM_ERRNO_EBADSLT:
+		return -EBADSLT;
+	case -DLM_ERRNO_EPROTO:
+		return -EPROTO;
+	case -DLM_ERRNO_EOPNOTSUPP:
+		return -EOPNOTSUPP;
+	case -DLM_ERRNO_ETIMEDOUT:
+		return -ETIMEDOUT;
+	case -DLM_ERRNO_EINPROGRESS:
+		return -EINPROGRESS;
+	}
+	return err;
+}