[dm-devel] [PATCH 2/2] dm-bufio: initialize read-only module parameters

[Mikulas Patocka]

dm-stats: initialize read-only module parameters

The module parameter stats_current_allocated_bytes in dm-mod is read-only.
This parameter informs the user about memory consumption. It is not
supposed to be changed by the user.

However, despite being read-only, this parameter can be set on modprobe or
insmod command line:
modprobe dm-mod stats_current_allocated_bytes=12345

The kernel doesn't expect that this variable can be non-zero at module
initialization and if the user sets it, it results in warning.

This patch initializates the variable in the module init routine, so that
user-supplied value is ignored.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Cc: stable at kernel.org	# 3.12+

---
 drivers/md/dm-bufio.c |    5 +++++
 drivers/md/dm-stats.c |    1 +
 2 files changed, 6 insertions(+)

Index: linux-3.13-rc2/drivers/md/dm-stats.c
===================================================================
--- linux-3.13-rc2.orig/drivers/md/dm-stats.c	2013-12-05 23:08:37.000000000 +0100
+++ linux-3.13-rc2/drivers/md/dm-stats.c	2013-12-05 23:09:00.000000000 +0100
@@ -964,6 +964,7 @@ int dm_stats_message(struct mapped_devic
 
 int __init dm_statistics_init(void)
 {
+	shared_memory_amount = 0;
 	dm_stat_need_rcu_barrier = 0;
 	return 0;
 }