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

Eric W. Biederman
2009-06-09T06:43:20Z

Linus Torvalds <torvalds@linux-foundation.org> writes:

> 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.

That sounds doable. Has that code been merged yet?

I took a quick look and it didn't see anyone breaking out of page fault with a
signal or code to really handle that.

Eric