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, 42 insertions, 0 deletions

diff --git a/drivers/edac/wq.c b/drivers/edac/wq.c
new file mode 100644
index 000000000..ad3f51662
--- /dev/null
+++ b/drivers/edac/wq.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "edac_module.h"
+
+static struct workqueue_struct *wq;
+
+bool edac_queue_work(struct delayed_work *work, unsigned long delay)
+{
+	return queue_delayed_work(wq, work, delay);
+}
+EXPORT_SYMBOL_GPL(edac_queue_work);
+
+bool edac_mod_work(struct delayed_work *work, unsigned long delay)
+{
+	return mod_delayed_work(wq, work, delay);
+}
+EXPORT_SYMBOL_GPL(edac_mod_work);
+
+bool edac_stop_work(struct delayed_work *work)
+{
+	bool ret;
+
+	ret = cancel_delayed_work_sync(work);
+	flush_workqueue(wq);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(edac_stop_work);
+
+int edac_workqueue_setup(void)
+{
+	wq = alloc_ordered_workqueue("edac-poller", WQ_MEM_RECLAIM);
+	if (!wq)
+		return -ENODEV;
+	else
+		return 0;
+}
+
+void edac_workqueue_teardown(void)
+{
+	destroy_workqueue(wq);
+	wq = NULL;
+}