EDAC: Rework workqueue handling

Hide the EDAC workqueue pointer in a separate compilation unit and add
accessors for the workqueue manipulations needed.

Remove edac_pci_reset_delay_period() which wasn't used by anything. It
seems it got added without a user with

  91b99041c1d5 ("drivers/edac: updated PCI monitoring")

Signed-off-by: Borislav Petkov <bp@suse.de>
diff --git a/drivers/edac/wq.c b/drivers/edac/wq.c
new file mode 100644
index 0000000..1b8c07e
--- /dev/null
+++ b/drivers/edac/wq.c
@@ -0,0 +1,42 @@
+#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 = create_singlethread_workqueue("edac-poller");
+	if (!wq)
+		return -ENODEV;
+	else
+		return 0;
+}
+
+void edac_workqueue_teardown(void)
+{
+	flush_workqueue(wq);
+	destroy_workqueue(wq);
+	wq = NULL;
+}