Re: rmmod while module is in use

[linux-os <linux-os@analogic.com>]

On Thu, 17 Feb 2005, Davide Rossetti wrote:

> maybe RTFM...
> a module:
> - char device driver for..
> - a PCI device
>
> any clue as to how to protect from module unloading while there is still some 
> process opening it??? have I to sleep in the remove_one() pci driver function 
> till last process closes its file descriptor???
>

The kernel code is supposed to prevent module removal when it
is still in use. Have you discovered a bug where the kernel
will allow unloading when it's still being used???

There used to be MOD_INC_USE_COUNT and MOD_DEC_USE_COUNT
macros to be using in open() and close(). However their
use has been depreciated in favor of some internal kernel
magic. So, unless you have discovered a bug, your code
doesn't have to worry anymore.

> static void __devexit apedev_remove_one(struct pci_dev *pdev)
> {
>   ApeDev* apedev = pci_get_drvdata(pdev);
>
>   if(test_bit(APEDEV_FLAG_OPEN, &apedev->flags)) {
>       PERROR("still open flag on!!! (flags=0x%08x)\n", apedev->flags);
>
>       // sleep here till it gets closed...
>
>   }
>   ...
> }
>
> static struct pci_driver apedev_driver = {
>   .name     =  DEVNAME,
>   .id_table =  apedev_pci_tbl,
>   .probe    =  apedev_init_one,
>   .remove   =  __devexit_p(apedev_remove_one),
> };
>

Cheers,
Dick Johnson
Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
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