Re: [PATCH 5/5] x86,mm: make pagefault killable

From: Linus Torvalds
Date: Wed Mar 23 2011 - 10:35:37 EST


On Wed, Mar 23, 2011 at 1:09 AM, KOSAKI Motohiro
<kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>
> When __lock_page_or_retry() return 0, It call up_read(mmap_sem) in this
> function.

Indeed.

> I agree this is strange (or ugly). but I don't want change this spec in
> this time.

I agree that it is strange, and I don't like functions that touch
locks that they didn't take themselves, but since the original point
of the whole thing was to wait for the page without holding the
mmap_sem lock, that function has to do the up_read() early.

Linus
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