Re: [PATCH 0/23] File descriptor hot-unplug support v2

Linus Torvalds
2009-06-08T19:16:19Z

On Mon, 8 Jun 2009, Al Viro wrote:
>
> Sure, even though I'm not at all certain that copy_from_user() is that easy.
> We can make locking current->mm in there interruptible, all right, but that's
> only a part of the answer - even aside of the allocations, we'd need vma
> ->fault() interruptible as well, which leads to interruptible instances of
> ->readpage(), with all the fun _that_ would be.

We already have all that - the NFS people wanted it.

More importantly, you don't actually need to interrupt readpage itself -
you just need to stop _waiting_ on it. So in your fault handler, just stop
waiting, and instead just return FAULT_RETRY or whatever.

Linus