From: Christophe JAILLET <christophe.jail...@wanadoo.fr>

'struct ref_scale_ops' are not modified in these drivers.

Constifying this structure moves some data to a read-only section, so
increase overall security.

On a x86_64, with allmodconfig:
Before:
======
   text    data     bss     dec     hex filename
  34231    4167     736   39134    98de kernel/rcu/refscale.o

After:
=====
   text    data     bss     dec     hex filename
  35175    3239     736   39150    98ee kernel/rcu/refscale.o

Signed-off-by: Christophe JAILLET <christophe.jail...@wanadoo.fr>
Tested-by: "Paul E. McKenney" <paul...@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadh...@kernel.org>
---
 kernel/rcu/refscale.c | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index cfec0648e141..0db9db73f57f 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -135,7 +135,7 @@ struct ref_scale_ops {
        const char *name;
 };
 
-static struct ref_scale_ops *cur_ops;
+static const struct ref_scale_ops *cur_ops;
 
 static void un_delay(const int udl, const int ndl)
 {
@@ -171,7 +171,7 @@ static bool rcu_sync_scale_init(void)
        return true;
 }
 
-static struct ref_scale_ops rcu_ops = {
+static const struct ref_scale_ops rcu_ops = {
        .init           = rcu_sync_scale_init,
        .readsection    = ref_rcu_read_section,
        .delaysection   = ref_rcu_delay_section,
@@ -205,7 +205,7 @@ static void srcu_ref_scale_delay_section(const int nloops, 
const int udl, const
        }
 }
 
-static struct ref_scale_ops srcu_ops = {
+static const struct ref_scale_ops srcu_ops = {
        .init           = rcu_sync_scale_init,
        .readsection    = srcu_ref_scale_read_section,
        .delaysection   = srcu_ref_scale_delay_section,
@@ -232,7 +232,7 @@ static void rcu_tasks_ref_scale_delay_section(const int 
nloops, const int udl, c
                un_delay(udl, ndl);
 }
 
-static struct ref_scale_ops rcu_tasks_ops = {
+static const struct ref_scale_ops rcu_tasks_ops = {
        .init           = rcu_sync_scale_init,
        .readsection    = rcu_tasks_ref_scale_read_section,
        .delaysection   = rcu_tasks_ref_scale_delay_section,
@@ -271,7 +271,7 @@ static void rcu_trace_ref_scale_delay_section(const int 
nloops, const int udl, c
        }
 }
 
-static struct ref_scale_ops rcu_trace_ops = {
+static const struct ref_scale_ops rcu_trace_ops = {
        .init           = rcu_sync_scale_init,
        .readsection    = rcu_trace_ref_scale_read_section,
        .delaysection   = rcu_trace_ref_scale_delay_section,
@@ -310,7 +310,7 @@ static void ref_refcnt_delay_section(const int nloops, 
const int udl, const int
        }
 }
 
-static struct ref_scale_ops refcnt_ops = {
+static const struct ref_scale_ops refcnt_ops = {
        .init           = rcu_sync_scale_init,
        .readsection    = ref_refcnt_section,
        .delaysection   = ref_refcnt_delay_section,
@@ -347,7 +347,7 @@ static void ref_rwlock_delay_section(const int nloops, 
const int udl, const int
        }
 }
 
-static struct ref_scale_ops rwlock_ops = {
+static const struct ref_scale_ops rwlock_ops = {
        .init           = ref_rwlock_init,
        .readsection    = ref_rwlock_section,
        .delaysection   = ref_rwlock_delay_section,
@@ -384,7 +384,7 @@ static void ref_rwsem_delay_section(const int nloops, const 
int udl, const int n
        }
 }
 
-static struct ref_scale_ops rwsem_ops = {
+static const struct ref_scale_ops rwsem_ops = {
        .init           = ref_rwsem_init,
        .readsection    = ref_rwsem_section,
        .delaysection   = ref_rwsem_delay_section,
@@ -419,7 +419,7 @@ static void ref_lock_delay_section(const int nloops, const 
int udl, const int nd
        preempt_enable();
 }
 
-static struct ref_scale_ops lock_ops = {
+static const struct ref_scale_ops lock_ops = {
        .readsection    = ref_lock_section,
        .delaysection   = ref_lock_delay_section,
        .name           = "lock"
@@ -454,7 +454,7 @@ static void ref_lock_irq_delay_section(const int nloops, 
const int udl, const in
        preempt_enable();
 }
 
-static struct ref_scale_ops lock_irq_ops = {
+static const struct ref_scale_ops lock_irq_ops = {
        .readsection    = ref_lock_irq_section,
        .delaysection   = ref_lock_irq_delay_section,
        .name           = "lock-irq"
@@ -490,7 +490,7 @@ static void ref_acqrel_delay_section(const int nloops, 
const int udl, const int
        preempt_enable();
 }
 
-static struct ref_scale_ops acqrel_ops = {
+static const struct ref_scale_ops acqrel_ops = {
        .readsection    = ref_acqrel_section,
        .delaysection   = ref_acqrel_delay_section,
        .name           = "acqrel"
@@ -524,7 +524,7 @@ static void ref_clock_delay_section(const int nloops, const 
int udl, const int n
        stopopts = x;
 }
 
-static struct ref_scale_ops clock_ops = {
+static const struct ref_scale_ops clock_ops = {
        .readsection    = ref_clock_section,
        .delaysection   = ref_clock_delay_section,
        .name           = "clock"
@@ -556,7 +556,7 @@ static void ref_jiffies_delay_section(const int nloops, 
const int udl, const int
        stopopts = x;
 }
 
-static struct ref_scale_ops jiffies_ops = {
+static const struct ref_scale_ops jiffies_ops = {
        .readsection    = ref_jiffies_section,
        .delaysection   = ref_jiffies_delay_section,
        .name           = "jiffies"
@@ -706,9 +706,9 @@ static void refscale_typesafe_ctor(void *rtsp_in)
        preempt_enable();
 }
 
-static struct ref_scale_ops typesafe_ref_ops;
-static struct ref_scale_ops typesafe_lock_ops;
-static struct ref_scale_ops typesafe_seqlock_ops;
+static const struct ref_scale_ops typesafe_ref_ops;
+static const struct ref_scale_ops typesafe_lock_ops;
+static const struct ref_scale_ops typesafe_seqlock_ops;
 
 // Initialize for a typesafe test.
 static bool typesafe_init(void)
@@ -769,7 +769,7 @@ static void typesafe_cleanup(void)
 }
 
 // The typesafe_init() function distinguishes these structures by address.
-static struct ref_scale_ops typesafe_ref_ops = {
+static const struct ref_scale_ops typesafe_ref_ops = {
        .init           = typesafe_init,
        .cleanup        = typesafe_cleanup,
        .readsection    = typesafe_read_section,
@@ -777,7 +777,7 @@ static struct ref_scale_ops typesafe_ref_ops = {
        .name           = "typesafe_ref"
 };
 
-static struct ref_scale_ops typesafe_lock_ops = {
+static const struct ref_scale_ops typesafe_lock_ops = {
        .init           = typesafe_init,
        .cleanup        = typesafe_cleanup,
        .readsection    = typesafe_read_section,
@@ -785,7 +785,7 @@ static struct ref_scale_ops typesafe_lock_ops = {
        .name           = "typesafe_lock"
 };
 
-static struct ref_scale_ops typesafe_seqlock_ops = {
+static const struct ref_scale_ops typesafe_seqlock_ops = {
        .init           = typesafe_init,
        .cleanup        = typesafe_cleanup,
        .readsection    = typesafe_read_section,
@@ -1026,7 +1026,7 @@ static int main_func(void *arg)
 }
 
 static void
-ref_scale_print_module_parms(struct ref_scale_ops *cur_ops, const char *tag)
+ref_scale_print_module_parms(const struct ref_scale_ops *cur_ops, const char 
*tag)
 {
        pr_alert("%s" SCALE_FLAG
                 "--- %s:  verbose=%d verbose_batched=%d shutdown=%d holdoff=%d 
lookup_instances=%ld loops=%ld nreaders=%d nruns=%d readdelay=%d\n", 
scale_type, tag,
@@ -1081,7 +1081,7 @@ ref_scale_init(void)
 {
        long i;
        int firsterr = 0;
-       static struct ref_scale_ops *scale_ops[] = {
+       static const struct ref_scale_ops *scale_ops[] = {
                &rcu_ops, &srcu_ops, RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, 
&rwlock_ops,
                &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &clock_ops, 
&jiffies_ops,
                &typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops,
-- 
2.40.1


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