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authorBrian Norris <computersforpeace@gmail.com>2015-06-01 16:17:20 -0700
committerBrian Norris <computersforpeace@gmail.com>2015-10-26 14:34:07 -0700
commitbe0dbff8b46d69bd738f63b4fe0cf64417f776b0 (patch)
tree044a2240eba4a10e2a8d920ecd2119e19d84b3de /drivers/mtd/mtdcore.c
parent3e00ed0e984bbec47f5e531bad3cf36885aa5d83 (diff)
downloadlinux-be0dbff8b46d69bd738f63b4fe0cf64417f776b0.tar.gz
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>
Diffstat (limited to 'drivers/mtd/mtdcore.c')
-rw-r--r--drivers/mtd/mtdcore.c9
1 files changed, 9 insertions, 0 deletions
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);