EDAC: Add routine to check if MC devices list is empty

We need to know if any MC devices have been allocated.

Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1485537863-2707-7-git-send-email-Yazen.Ghannam@amd.com
[ Prettify text. ]
Signed-off-by: Borislav Petkov <bp@suse.de>

drivers/edac/edac_mc.c

@@ -453,6 +453,20 @@ void edac_mc_free(struct mem_ctl_info *mci)
 }
 EXPORT_SYMBOL_GPL(edac_mc_free);
 
+bool edac_has_mcs(void)
+{
+	bool ret;
+
+	mutex_lock(&mem_ctls_mutex);
+
+	ret = list_empty(&mc_devices);
+
+	mutex_unlock(&mem_ctls_mutex);
+
+	return !ret;
+}
+EXPORT_SYMBOL_GPL(edac_has_mcs);
+
 /* Caller must hold mem_ctls_mutex */
 static struct mem_ctl_info *__find_mci_by_dev(struct device *dev)
 {

drivers/edac/edac_mc.h

@@ -148,6 +148,15 @@ extern int edac_mc_add_mc_with_groups(struct mem_ctl_info *mci,
  */
 extern void edac_mc_free(struct mem_ctl_info *mci);
 
+/**
+ * edac_has_mcs() - Check if any MCs have been allocated.
+ *
+ * Returns:
+ *	True if MC instances have been registered successfully.
+ *	False otherwise.
+ */
+extern bool edac_has_mcs(void);
+
 /**
  * edac_mc_find() - Search for a mem_ctl_info structure whose index is @idx.
  *