rcu: Make rcutree module parameters visible in sysfs

The module parameters blimit, qhimark, and qlomark (and more
recently, rcu_fanout_leaf) have permission masks of zero, so
that their values are not visible from sysfs.  This is unnecessary
and inconvenient to administrators who might like an easy way to
see what these values are on a running system.  This commit therefore
sets their permission masks to 0444, allowing them to be read but
not written.

Suggested-by: Rusty Russell <rusty@ozlabs.org>
Suggested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 1d3324082e531a2b304b0862318d8ee3152c83ef..55f20fd25d0e9f58deff612c883d1e59d3354786 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -88,7 +88,7 @@ LIST_HEAD(rcu_struct_flavors);
 
 /* Increase (but not decrease) the CONFIG_RCU_FANOUT_LEAF at boot time. */
 static int rcu_fanout_leaf = CONFIG_RCU_FANOUT_LEAF;
-module_param(rcu_fanout_leaf, int, 0);
+module_param(rcu_fanout_leaf, int, 0444);
 int rcu_num_lvls __read_mostly = RCU_NUM_LVLS;
 static int num_rcu_lvl[] = {  /* Number of rcu_nodes at specified level. */
        NUM_RCU_LVL_0,
@@ -216,9 +216,9 @@ static int blimit = 10;             /* Maximum callbacks per rcu_do_batch. */
 static int qhimark = 10000;    /* If this many pending, ignore blimit. */
 static int qlowmark = 100;     /* Once only this many pending, use blimit. */
 
-module_param(blimit, int, 0);
-module_param(qhimark, int, 0);
-module_param(qlowmark, int, 0);
+module_param(blimit, int, 0444);
+module_param(qhimark, int, 0444);
+module_param(qlowmark, int, 0444);
 
 int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
 int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;