Feather-Trace: dynamic memory allocation and clean exit2011.1

This patch changes Feather-Trace to allocate memory for the minor
devices dynamically, which addresses a long-standing FIXME. It also
provides clean module exit and error conditions for Feather-Trace.

1 files changed, 28 insertions, 7 deletions

diff --git a/litmus/sched_task_trace.c b/litmus/sched_task_trace.c
index 7ef7b2889b42..a15b25d21a89 100644
--- a/litmus/sched_task_trace.c
+++ b/litmus/sched_task_trace.c
@@ -38,12 +38,17 @@ static int st_dev_can_open(struct ftdev *dev, unsigned int cpu)
 static int __init init_sched_task_trace(void)
 {
         struct local_buffer* buf;
-        int i, ok = 0;
+        int i, ok = 0, err;
         printk("Allocated %u sched_trace_xxx() events per CPU "
                "(buffer size: %d bytes)\n",
                NO_EVENTS, (int) sizeof(struct local_buffer));
-        ftdev_init(&st_dev, THIS_MODULE, "sched_trace");
-        for (i = 0; i < NR_CPUS; i++) {
+
+        err = ftdev_init(&st_dev, THIS_MODULE,
+                        num_online_cpus(), "sched_trace");
+        if (err)
+                goto err_out;
+
+        for (i = 0; i < st_dev.minor_cnt; i++) {
                 buf = &per_cpu(st_event_buffer, i);
                 ok += init_ft_buffer(&buf->ftbuf, NO_EVENTS,
                                      sizeof(struct st_event_record),
@@ -51,16 +56,32 @@ static int __init init_sched_task_trace(void)
                                      buf->record);
                 st_dev.minor[i].buf = &buf->ftbuf;
         }
-        if (ok == NR_CPUS) {
-                st_dev.minor_cnt = NR_CPUS;
+        if (ok == st_dev.minor_cnt) {
                 st_dev.can_open = st_dev_can_open;
-                return register_ftdev(&st_dev);
+                err = register_ftdev(&st_dev);
+                if (err)
+                        goto err_dealloc;
         } else {
-                return -EINVAL;
+                err = -EINVAL;
+                goto err_dealloc;
         }
+
+        return 0;
+
+err_dealloc:
+        ftdev_exit(&st_dev);
+err_out:
+        printk(KERN_WARNING "Could not register sched_trace module\n");
+        return err;
+}
+
+static void __exit exit_sched_task_trace(void)
+{
+        ftdev_exit(&st_dev);
 }
 
 module_init(init_sched_task_trace);
+module_exit(exit_sched_task_trace);
 
 
 static inline struct st_event_record* get_record(u8 type, struct task_struct* t)