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, 24 insertions, 3 deletions

diff --git a/litmus/trace.c b/litmus/trace.c
index da650dfe7f4d..e7ea1c2ab3e4 100644
--- a/litmus/trace.c
+++ b/litmus/trace.c
@@ -90,12 +90,33 @@ static void free_timestamp_buffer(struct ftdev* ftdev, unsigned int idx)
 
 static int __init init_ft_overhead_trace(void)
 {
+        int err;
+
         printk("Initializing Feather-Trace overhead tracing device.\n");
-        ftdev_init(&overhead_dev, THIS_MODULE, "ft_trace");
-        overhead_dev.minor_cnt = 1; /* only one buffer */
+        err = ftdev_init(&overhead_dev, THIS_MODULE, 1, "ft_trace");
+        if (err)
+                goto err_out;
+
         overhead_dev.alloc = alloc_timestamp_buffer;
         overhead_dev.free  = free_timestamp_buffer;
-        return register_ftdev(&overhead_dev);
+
+        err = register_ftdev(&overhead_dev);
+        if (err)
+                goto err_dealloc;
+
+        return 0;
+
+err_dealloc:
+        ftdev_exit(&overhead_dev);
+err_out:
+        printk(KERN_WARNING "Could not register ft_trace module.\n");
+        return err;
+}
+
+static void __exit exit_ft_overhead_trace(void)
+{
+        ftdev_exit(&overhead_dev);
 }
 
 module_init(init_ft_overhead_trace);
+module_exit(exit_ft_overhead_trace);