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Date:   Thu, 31 Jan 2019 17:00:10 +0100
From:   David Sterba <dsterba@suse.cz>
To:     Dennis Zhou <dennis@kernel.org>
Cc:     David Sterba <dsterba@suse.com>,
        Josef Bacik <josef@toxicpanda.com>, Chris Mason <clm@fb.com>,
        Omar Sandoval <osandov@osandov.com>,
        Nick Terrell <terrelln@fb.com>, kernel-team@fb.com,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/11] btrfs: add macros for compression type and level
Message-ID: <20190131160010.GK2900@twin.jikos.cz>
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        Nick Terrell <terrelln@fb.com>, kernel-team@fb.com,
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References: <20190128212437.11597-1-dennis@kernel.org>
 <20190128212437.11597-2-dennis@kernel.org>
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On Mon, Jan 28, 2019 at 04:24:27PM -0500, Dennis Zhou wrote:
> It is very easy to miss places that rely on a certain bitshifting for
> decyphering the type_level overloading. Make macros handle this instead.

This encoding was a simple way to introduce the combined type and level
for zlib and it could certainly be improved. Either we'll use helpers
like you suggest or add a new structure that contains type and level as
members. That way we'd see where the level still matters and where the
just the type is ok.

I haven't checked how much intrusive this would be, so that's for later
consideration. Some indirection can be removed for the .set_level
callbacks as it does not necessarily need to be a function so I'm
expecting that the code around that would be touched anyway.