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Date:   Fri, 4 Oct 2019 05:30:44 -0700
From:   Michel Lespinasse <walken@google.com>
To:     Davidlohr Bueso <dave@stgolabs.net>,
        Matthew Wilcox <willy@infradead.org>
Cc:     akpm@linux-foundation.org, peterz@infradead.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org,
        Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH 08/11] mm: convert vma_interval_tree to half closed
 intervals
Message-ID: <20191004123044.GA11046@google.com>
References: <20191003201858.11666-1-dave@stgolabs.net>
 <20191003201858.11666-9-dave@stgolabs.net>
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On Thu, Oct 03, 2019 at 01:18:55PM -0700, Davidlohr Bueso wrote:
> The vma and anon vma interval tree really wants [a, b) intervals,
> not fully closed. As such convert it to use the new
> interval_tree_gen.h. Because of vma_last_pgoff(), the conversion
> is quite straightforward.

I am not certain if we need to worry about integer overflow here.
The problem case would be accessing the last block of a file that is
exactly 16TB long, on an arch where long (and thus pgoff_t) is 32-bit.
Maybe FS folks can tell us whether that case is currently supported,
or if we can just not worry about it ?

I would also want to rename the fields in struct zap_details into
start_index and end_index so we can verify we don't leave any
off-by-one uses.

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.