On Fri, 3 May 2024 at 15:07, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> Suppose your program calls select() on a pipe and dmabuf, sees data to be read
> from pipe, reads it, closes both pipe and dmabuf and exits.
>
> Would you expect that dmabuf file would stick around for hell knows how long
> after that? I would certainly be very surprised by running into that...
Why?
That's the _point_ of refcounts. They make the thing they refcount
stay around until it's no longer referenced.
Now, I agree that dmabuf's are a bit odd in how they use a 'struct
file' *as* their refcount, but hey, it's a specialty use. Unusual
perhaps, but not exactly wrong.
I suspect that if you saw a dmabuf just have its own 'refcount_t' and
stay around until it was done, you wouldn't bat an eye at it, and it's
really just the "it uses a struct file for counting" that you are
reacting to.
Linus
