Re: [GIT PULL] pidfd updates

[Linus Torvalds]

On Mon, Apr 24, 2023 at 1:24 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> But I really think a potentially much nicer model would have been to
> extend our "get_unused_fd_flags()" model.
>
> IOW, we could have instead marked the 'struct file *' in the file
> descriptor table as being "not ready yet".

Maybe that isn't worth it just for pdfd, but I have this feeling that
it might make some other code simpler too.

That pidfd case isn't the only one that has to carry both a file
pointer and a fd around.

Looking around, I get the feeling that quite a lot of users of
"fd_install()" might actually have been happier if they could just
install it early, and then just have a "fd_expose(fd)" for the success
case, and for the error cases have "put_unused_fd(fd)" also do the
fput on the file descriptor even if the low bit was set. One less
thing to worry about.

I dunno. Maybe not worth it. That "two return values" just made me go "Eww".

               Linus