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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Wed, 19 Jul 2023 12:17:51 +0200
Message-ID: <CAJfpegsJuvXJDcXpo9T19Gw0tDuvyOJdv44Y2bt04MEf1JLxGg@mail.gmail.com>
Subject: Re: [RFC PATCH 1/4] splice: Fix corruption of spliced data after
 splice() returns
To:     David Howells <dhowells@redhat.com>
Cc:     netdev@vger.kernel.org, Matthew Wilcox <willy@infradead.org>,
        Dave Chinner <david@fromorbit.com>,
        Matt Whitlock <kernel@mattwhitlock.name>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jens Axboe <axboe@kernel.dk>, linux-fsdevel@kvack.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>, linux-fsdevel@vger.kernel.org
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On Thu, 29 Jun 2023 at 17:56, David Howells <dhowells@redhat.com> wrote:
>
> Splicing data from, say, a file into a pipe currently leaves the source
> pages in the pipe after splice() returns - but this means that those pages
> can be subsequently modified by shared-writable mmap(), write(),
> fallocate(), etc. before they're consumed.

What is this trying to fix?   The above behavior is well known, so
it's not likely to be a problem.

Besides, removing spliced pages from the cache is basically guaranteed
to result in a performance regression for any application using
splice.

Thanks,
Miklos