linux-ext4 - Re: [PATCH v10 02/12] block: Keyslot Manager for Inline Encryption

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Message-ID: <20200422092250.GA12290@infradead.org>
Date:   Wed, 22 Apr 2020 02:22:50 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Satya Tangirala <satyat@...gle.com>
Cc:     linux-block@...r.kernel.org, linux-scsi@...r.kernel.org,
        linux-fscrypt@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, linux-ext4@...r.kernel.org,
        Barani Muthukumaran <bmuthuku@....qualcomm.com>,
        Kuohong Wang <kuohong.wang@...iatek.com>,
        Kim Boojin <boojin.kim@...sung.com>,
        Eric Biggers <ebiggers@...gle.com>
Subject: Re: [PATCH v10 02/12] block: Keyslot Manager for Inline Encryption

> +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.