My driver write routine is not working properly.
As a result, when I do echo "123" > /dev/eater, the process is stopping and the control goes into an infinite loop.
lsmod showed my driver was in use by 2 processes.
Now if i want to forcefully remove my driver module from kernel, how to do that?
Below is the write routine:
static int eater_write(struct file *file, const char *buf, size_t lbuf, loff_t *ppos)
{
ÂÂÂÂÂÂÂ int actual_data_allowed_to_write;
ÂÂÂÂÂÂÂ int data_written;
ÂÂÂÂÂÂÂ int data_to_copy=0;
ÂÂÂÂÂÂÂ printk("requested bytes to write: %d\n", lbuf);
ÂÂÂÂÂÂÂ actual_data_allowed_to_write = MAXSIZE - *ppos;
ÂÂÂÂÂÂÂ printk("allowed bytes to write: %d\n", actual_data_allowed_to_write);
ÂÂÂÂÂÂÂ if(actual_data_allowed_to_write == 0)
ÂÂÂÂÂÂÂ {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ printk("Device has no space to write. format it\n");
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return(actual_data_allowed_to_write);
ÂÂÂÂÂÂÂ }
ÂÂÂÂÂÂÂ //if available space can accommodate data to write
ÂÂÂÂÂÂÂ if(actual_data_allowed_to_write > lbuf)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ data_to_copy=lbuf;
ÂÂÂÂÂÂÂ //if available space can't accommodate date to write
ÂÂÂÂÂÂÂ if(actual_data_allowed_to_write < lbuf)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ data_to_copy=actual_data_allowed_to_write;
ÂÂÂÂÂÂÂ printk("data_to_copy: %d\n", data_to_copy);
ÂÂÂÂÂÂÂ data_written=copy_from_user(eater_space + *ppos, /* to */ \
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ buf, /* from */ \
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ data_to_copy);
ÂÂÂÂÂÂÂ //update device memory with new position
ÂÂÂÂÂÂÂ *ppos += data_to_copy;
ÂÂÂÂÂÂÂ printk("\nWrote %d bytes\n", data_written);
ÂÂÂÂÂÂÂ return(data_written);
}
Appreciate any help.
/Sri.
