Re: [f2fs-dev] [PATCH v10 02/12] block: Keyslot Manager for Inline Encryption

From: Christoph Hellwig <hch@infradead.org>
To: Satya Tangirala <satyat@google.com>
Cc: linux-scsi@vger.kernel.org, Kim Boojin <boojin.kim@samsung.com>,
	Kuohong Wang <kuohong.wang@mediatek.com>,
	Eric Biggers <ebiggers@google.com>,
	Barani Muthukumaran <bmuthuku@qti.qualcomm.com>,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-block@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [f2fs-dev] [PATCH v10 02/12] block: Keyslot Manager for Inline Encryption
Date: Wed, 22 Apr 2020 02:22:50 -0700	[thread overview]
Message-ID: <20200422092250.GA12290@infradead.org> (raw)
In-Reply-To: <20200408035654.247908-3-satyat@google.com>

> +bool blk_ksm_crypto_cfg_supported(struct blk_keyslot_manager *ksm,
> +				  const struct blk_crypto_config *cfg)
> +{
> +	if (!ksm)
> +		return false;
> +	return (ksm->crypto_modes_supported[cfg->crypto_mode] &
> +		cfg->data_unit_size) &&
> +	       (ksm->max_dun_bytes_supported >= cfg->dun_bytes);

Nit: why not expand this a bit to be more readable:

	if (!(ksm->crypto_modes_supported[cfg->crypto_mode] &
			cfg->data_unit_size))
		return false;
	if (ksm->max_dun_bytes_supported < cfg->dun_bytes)
		return false;
	return true;

> +int blk_ksm_evict_key(struct blk_keyslot_manager *ksm,
> +		      const struct blk_crypto_key *key)
> +{
> +	struct blk_ksm_keyslot *slot;
> +	int err = 0;
> +
> +	blk_ksm_hw_enter(ksm);
> +	slot = blk_ksm_find_keyslot(ksm, key);
> +	if (!slot)
> +		goto out_unlock;
> +
> +	if (atomic_read(&slot->slot_refs) != 0) {
> +		err = -EBUSY;
> +		goto out_unlock;
> +	}

This check looks racy.

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