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Message-ID: <1b49f7958c437878c5fc02cfb82c4ede1064bc08.camel@scylladb.com>
Subject: Re: [PATCH 17/20] aio: support for IO polling
From: Benny Halevy <bhalevy@scylladb.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-aio@kvack.org,
        linux-fsdevel@vger.kernel.org
Date: Thu, 29 Nov 2018 16:10:30 +0200
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On Wed, 2018-11-28 at 11:50 -0700, Jens Axboe wrote:
> On 11/28/18 2:33 AM, Benny Halevy wrote:
> > > I don't see how we can get there with it being larger than already,
> > > that would be a big bug if we fill more events than userspace asked
> > > for.
> > > 
> > 
> > Currently we indeed can't, but if the code changes in the future and
> > we do, this will reduce the damage - hence being safer (and it costs
> > nothing in terms of performance).
> 
> The thing is, if we're ever over max, we have potentially corrupted user
> space memory by copying back too many events. So if anything, it should
> be a BUG() condition, not just a check.
> 

Agreed.