stm class: stm_heartbeat: Make nr_devs parameter read-only

Changing nr_devs after the module has been loaded doesn't actually
change anything, so just make it read-only.

Reported-by: Alan Cox <alan.cox@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
(cherry picked from commit c8be4899449c0b27bc5daf71742cd601b2b3b4e3)

diff --git a/drivers/hwtracing/stm/heartbeat.c b/drivers/hwtracing/stm/heartbeat.c
index 0133571b506f3b62a6823e40d1287eec6d8ac6c4..3da7b673aab252a245991c901eb5a07696c5fb38 100644 (file)
--- a/drivers/hwtracing/stm/heartbeat.c
+++ b/drivers/hwtracing/stm/heartbeat.c
@@ -26,7 +26,7 @@
 static int nr_devs = 4;
 static int interval_ms = 10;
 
-module_param(nr_devs, int, 0600);
+module_param(nr_devs, int, 0400);
 module_param(interval_ms, int, 0600);
 
 static struct stm_heartbeat {
@@ -35,8 +35,6 @@ static struct stm_heartbeat {
        unsigned int            active;
 } stm_heartbeat[STM_HEARTBEAT_MAX];
 
-static unsigned int nr_instances;
-
 static const char str[] = "heartbeat stm source driver is here to serve you";
 
 static enum hrtimer_restart stm_heartbeat_hrtimer_handler(struct hrtimer *hr)
@@ -74,12 +72,12 @@ static void stm_heartbeat_unlink(struct stm_source_data *data)
 
 static int stm_heartbeat_init(void)
 {
-       int i, ret = -ENOMEM, __nr_instances = ACCESS_ONCE(nr_devs);
+       int i, ret = -ENOMEM;
 
-       if (__nr_instances < 0 || __nr_instances > STM_HEARTBEAT_MAX)
+       if (nr_devs < 0 || nr_devs > STM_HEARTBEAT_MAX)
                return -EINVAL;
 
-       for (i = 0; i < __nr_instances; i++) {
+       for (i = 0; i < nr_devs; i++) {
                stm_heartbeat[i].data.name =
                        kasprintf(GFP_KERNEL, "heartbeat.%d", i);
                if (!stm_heartbeat[i].data.name)
@@ -98,8 +96,6 @@ static int stm_heartbeat_init(void)
                        goto fail_free;
        }
 
-       nr_instances = __nr_instances;
-
        return 0;
 
 fail_unregister:
@@ -116,7 +112,7 @@ static void stm_heartbeat_exit(void)
 {
        int i;
 
-       for (i = 0; i < nr_instances; i++) {
+       for (i = 0; i < nr_devs; i++) {
                stm_source_unregister_device(&stm_heartbeat[i].data);
                kfree(stm_heartbeat[i].data.name);
        }