Re: Problems with close() system call

[Raj <inguva@gmail.com>]

On Tue, 26 Oct 2004 17:43:36 +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
> 
> Uh, then something's wrong. Your device fops should look like this:
> {
>   .release = my_close, // which is called upon close(2)
> }
> 
> Anything else is of course, never working.

iirc, once i faced this problem. I compiled a sample device driver
against kernel version
'X'. and tried to insmod the binary into kernel version 'Y' which had
it's fop's struct
modified. The structure offsets took a beating and all hell broke
loose. Calling open()
called something else etc.... Ever since, i started using the above notation to
initialize struct members. Hard learned lesson ;-)

-- 
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raj
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