Re: [PATCH 3/3] Add a pair of system calls to make extended file stats available [ver #2]

From: David Howells
Date: Wed Jun 30 2010 - 08:14:28 EST

Arnd Bergmann <arnd@xxxxxxxx> wrote:

> Given a 64 bit flag word, you can start using bits for the version from
> the top and bits from the bottom for fields:

I suppose. It's cleaner, though, to keep them separate.

> Alternatively, you can also make it a 64 bit argument everywhere, which has
> some other small disadvantages.

No, you can't. 32-bit systems can only pass 32-bit arguments. If you're
suggesting passing a pointer to a 64-bit argument instead, how's that any
different from my suggestion of a separate parameter block?

> The idea of a syscall API with multiple fixed-length and variable-length
> fields in the same structure scares me. If you want to go this far,
> it may be better to base the interface on netlink and allow querying
> multiple files at once.

Urgh. Netlink is way too much overhead and even scarier. That's pretty much
a guarantee that people won't use it. It also has to work if CONFIG_NET=n.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at