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Date:   Thu, 27 Feb 2020 10:14:11 -0800
From:   Eric Biggers <ebiggers@kernel.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Satya Tangirala <satyat@google.com>, linux-block@vger.kernel.org,
        linux-scsi@vger.kernel.org, linux-fscrypt@vger.kernel.org,
        linux-fsdevel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, linux-ext4@vger.kernel.org,
        Barani Muthukumaran <bmuthuku@qti.qualcomm.com>,
        Kuohong Wang <kuohong.wang@mediatek.com>,
        Kim Boojin <boojin.kim@samsung.com>
Subject: Re: [PATCH v7 1/9] block: Keyslot Manager for Inline Encryption
Message-ID: <20200227181411.GB877@sol.localdomain>
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 <20200221115050.238976-2-satyat@google.com>
 <20200221170434.GA438@infradead.org>
 <20200221173118.GA30670@infradead.org>
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On Fri, Feb 21, 2020 at 09:31:18AM -0800, Christoph Hellwig wrote:
> On Fri, Feb 21, 2020 at 09:04:34AM -0800, Christoph Hellwig wrote:
> > Given that blk_ksm_get_slot_for_key returns a signed keyslot that
> > can return errors, and the only callers stores it in a signed variable
> > I think this function should take a signed slot as well, and the check
> > for a non-negative slot should be moved here from the only caller.
> 
> Actually looking over the code again I think it might be better to
> return only the error code (and that might actually be a blk_status_t),
> and then use an argument to return a pointer to the actual struct
> keyslot.  That gives us much easier to understand code and better
> type safety.

That doesn't make sense because the caller only cares about the keyslot number,
not the 'struct keyslot'.  The 'struct keyslot' is internal to
keyslot-manager.c, as it only contains keyslot management information.

Your earlier suggestion of making blk_ksm_put_slot() be a no-op on a negative
keyslot number sounds fine though.

- Eric