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    SubjectRe: [PATCH] remove BKL from drivers' release functions
    On Wed, Nov 28, 2001 at 04:26:16PM -0800, David C. Hansen wrote:
    > I wrote a quick and dirty char device driver to see if this happened.
    > If I run two tasks doing a bunch of opens and closes, the -EBUSY
    > condition in the open function does happen. Is my driver doing
    > something wrong?

    What's happening is:

    task 1 task 2
    -> sys_open
    -> lock_kernel
    -> testdev_open
    -> test_and_set_bit
    return success
    unlock kernel
    -> sys_open
    -> lock_kernel (blocks on it)
    -> testdev_open
    -> test_and_set_bit
    return -EBUSY
    unlock kernel
    return
    return

    The BKL is only held for the duration of the open, not until you close the
    device.

    --
    Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
    http://www.arm.linux.org.uk/personal/aboutme.html

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