From: Brian Norris Date: Mon, 1 Jun 2015 23:17:20 +0000 (-0700) Subject: mtd: warn when registering the same master many times X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=be0dbff8b46d69bd738f63b4fe0cf64417f776b0;p=linux-beck.git 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 Reviewed-by: Richard Weinberger --- diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index a2e76ac9f1dc..41dc501cb49a 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -387,6 +387,14 @@ int add_mtd_device(struct mtd_info *mtd) 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 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types, * 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);