Strange behavior for create_proc_read_entry

[Prashant Shah <pshah.mumbai@xxxxxxxxx>]

Hi,

Below is a small module that I was trying out (code at the end of message)

This module creates a file called /proc/jiffies that adds a message to
the log file using printk and shows the current jiffies value to the
user when it is read.

If I cat the /proc/jiffies file once, in the dmesg log there are three
entries. The function create_proc_read_entry() is calling the
my_proc_read() thrice.

o/p :
[  997.261195] ******** Reading jiffies files *********
[  997.261205] ******** Reading jiffies files *********
[  997.261233] ******** Reading jiffies files *********

-------------- module code ---------------

#include <linux/module.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>

#define SUCCESS 0
static char modname[] = "jiffies";

static int my_proc_read(char *buf, char **start, off_t off,
                int count, int *eof, void *data)
{
        printk("******** Reading jiffies files *********\n");
        return sprintf(buf, "jiffies = %lu\n", jiffies);
}

static int __init mod_entry(void)
{
        printk(KERN_INFO "***** START *******\n");
        create_proc_read_entry(modname, 0, NULL, my_proc_read, NULL);
        return SUCCESS;
}

static void __exit mod_exit(void)
{
        printk("******** END *********\n");
        remove_proc_entry(modname, NULL);
        return;
}
MODULE_LICENSE("GPL");
module_init(mod_entry);
module_exit(mod_exit);
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