Am Freitag, 16. Februar 2007 12:40 schrieb Samuel Ortiz:
> Oliver Neukum wrote:
> > Am Freitag, 16. Februar 2007 09:41 schrieb Samuel Ortiz:
> >
> >> One stupid question: Suppose we're in iowarrior_read(), got a pointer on
> >> private_data, but haven't taken the mutex yet. iowarrior_release() is
> >> called, locks the mutex, decrements the opened counter to 0, and then
> >> call iowarrior_delete(). iowarrior_read() resumes, and tries to grab
> >> dev->mutex, but at that point dev is NULL, and we oops. How is that case
> >> handled ?
> >
> > How do you close a file you are reading from? In a threaded task
> > you can call close and read simultaneously, but the release method
> > is called only when the last thread closes the fd.
> Well, two process would share the same dev pointer, and I was thinking
> of process A closing the file and thus freeing dev while process B was
> in read(). But the driver doesn't allow multiple multiple open(), so
> that's taken care of.
struct file * is private to each task. One task closing it doesn't affect the
other tasks having opened the same device.
Regards
Oliver
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