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From:   David Howells <dhowells@redhat.com>
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To:     Matthew Wilcox <willy@infradead.org>
Cc:     dhowells@redhat.com,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>, Ted Ts'o <tytso@mit.edu>,
        Dave Hansen <dave.hansen@linux.intel.com>,
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Subject: Re: Do we need to unrevert "fs: do not prefault sys_write() user buffer pages"?
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Date:   Tue, 22 Jun 2021 19:13:02 +0100
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Matthew Wilcox <willy@infradead.org> wrote:

> > It may also cause the read in to happen in the background whilst write=
_begin
> > is being done.
> =

> Huh?  Last I checked, the fault_in_readable actually read a byte from
> the page.  It has to wait for the read to complete before that can
> happen.

Ah, good point.

David