Re: Problems with close() system call

[Arne Henrichsen <ahenric@gmail.com>]

On Tue, 26 Oct 2004 13:30:35 +0200 (MEST), Jan Engelhardt
<jengelh@linux01.gwdg.de> wrote:
> 
> Best is to put a printk("i'm in ioctl()") in the ioctl() function and a
> printk("i'm in close()") in the close() one, to be really sure whether the
> close() function of your module is called.
> 

Yes, that is exactly what I am doing. I basically implement the
flush() call (for close) as the release() call was never called on
close. So my release call does nothing. What I see is that the flush
function gets called, even though I have never called the close()
system call from my user app.

I also print out the module counter, and it doesn't make sense who
increments it:

open(0): f_count = 1
ioctl(0): f_count = 2
ioctl(0): f_count = 5
open(1)): f_count = 1
ioctl(1): f_count = 2
flush(0): f_count = 7
ioctl(1): f_count = 5
open(2): f_count = 1
ioctl(2): f_count = 2
flush(1): f_count = 7

My user app looks something like this:
int fd[8];

for(i = 0; i < nr_dev; i)
  {
    sprintf(dev, "/dev/mydev_%c", '0' + i);
    fd[i] = open(dev, O_RDWR | O_SYNC);
    if(fd[i] < 0)
    {
      printf("Error opening device: %s - %s\n", dev, strerror(errno));
      goto test_error;
    }

    status = ioctl(fd[i], CMD1);
    if(status != 0)
    {
      printf("%s - %s\n", dev, strerror(errno));
    }

    status = ioctl(fd[i], CMD2);
    if(status != 0)
    {
      printf("%s - %s\n", dev, strerror(errno));
    }
  } /* for(port_id = 0; port_id < nr_ports; port_id++) */
  
Arne