mtd: warn when registering the same master many times
When CONFIG_MTD_PARTITIONED_MASTER=y, it is fatal to call
mtd_device_parse_register() twice on the same MTD, as we try to register
the same device/kobject multipile times.
When CONFIG_MTD_PARTITIONED_MASTER=n, calling
mtd_device_parse_register() is more of just a nuisance, as we can mostly
navigate around any conflicting actions.
But anyway, doing so is a Bad Thing (TM), and we should complain loudly
for any drivers that try to do this.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index a2e76ac..41dc501 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -387,6 +387,14 @@
struct mtd_notifier *not;
int i, error;
+ /*
+ * May occur, for instance, on buggy drivers which call
+ * mtd_device_parse_register() multiple times on the same master MTD,
+ * especially with CONFIG_MTD_PARTITIONED_MASTER=y.
+ */
+ if (WARN_ONCE(mtd->backing_dev_info, "MTD already registered\n"))
+ return -EEXIST;
+
mtd->backing_dev_info = &mtd_bdi;
BUG_ON(mtd->writesize == 0);
@@ -606,6 +614,7 @@
* does cause problems with parse_mtd_partitions() above (e.g.,
* cmdlineparts will register partitions more than once).
*/
+ WARN_ONCE(mtd->reboot_notifier.notifier_call, "MTD already registered\n");
if (mtd->_reboot && !mtd->reboot_notifier.notifier_call) {
mtd->reboot_notifier.notifier_call = mtd_reboot_notifier;
register_reboot_notifier(&mtd->reboot_notifier);