Re: rmmod while module is in use

From: linux-os (linux-os_at_analogic.com)
Date: 02/17/05

  • Next message: Marc Cramdal: "AMD 64 and Kernel AGPart support" 
    Date:	Thu, 17 Feb 2005 08:04:13 -0500 (EST)
To: Davide Rossetti <davide.rossetti@roma1.infn.it>

    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,
    *** Johnson
    Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
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  • Next message: Marc Cramdal: "AMD 64 and Kernel AGPart support"