Hi,
I am trying to learn module development in Linux Kernel and I wanted to know how to use a tracepoint already defined in the linux kernel :
http://kernel.org/doc/htmldocs/trace...-complete.html
The tracepoint I am referring to is :
trace_block_bio_complete();
As per the documentation it says that trace_block_bio_complete() is called when the Block operation is completed :
This tracepoint indicates there is no further work to do on this block IO operation bio.
But when I write a KERNEL Module for the same, its not working. Here is the code :
Code:
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/blktrace_api.h>
#include <linux/percpu.h>
#include <linux/bio.h>
#include <linux/tracepoint.h>
MODULE_LICENSE("Dual BSD/GPL");
int mymod_count = 0;
static void mymod_trace_bio_complete(struct request_queue *q, struct bio *bio)
{
if(mymod_count < 10){
printk(KERN_INFO "%d ... \n", mymod_count);
}
mymod_count++;
}
static int mymod_init(void) {
int ret;
printk("<1> Starting mymod kernel module ... \n");
ret = register_trace_block_bio_complete(mymod_trace_bio_complete);
WARN_ON(ret);
}
static void mymod_exit(void) {
printk("<1> Stopping mymod kernel module ... \n");
unregister_trace_block_bio_complete(mymod_trace_bio_complete);
}
module_init(mymod_init);
module_exit(mymod_exit);
Please let me know what I am doing wrong. Also I dont know if there is any dedicated forum or mailing list where I can ask questions about kernel development.
Looking forward to any input
