Re: [PATCH v8 03/11] block: Make blk-integrity preclude hardware inline encryption

[Christoph Hellwig <hch@infradead.org>]

On Thu, Mar 12, 2020 at 01:02:45AM -0700, Satya Tangirala wrote:
> There's no hardware currently that supports both integrity and inline
> encryption. However, it seems possible that there will be in the near
> future, based on discussion at
> https://lore.kernel.org/r/20200108140730.GC2896@infradead.org/
> But properly integrating both features is not trivial, and without
> real hardware that implements both, it is difficult to tell if it will
> be done correctly by the majority of hardware that support both, and
> through discussions at
> https://lore.kernel.org/r/20200224233459.GA30288@infradead.org/
> it seems best not to support both features together right now, and
> to decide what to do at probe time.

Please don't reference web links, just inline the important information.

> diff --git a/block/bio-integrity.c b/block/bio-integrity.c
> index bf62c25cde8f..a5c57991c6fa 100644
> --- a/block/bio-integrity.c
> +++ b/block/bio-integrity.c
> @@ -42,6 +42,11 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
>  	struct bio_set *bs = bio->bi_pool;
>  	unsigned inline_vecs;
>  
> +	if (bio_has_crypt_ctx(bio)) {
> +		pr_warn("blk-integrity can't be used together with inline en/decryption.");
> +		return ERR_PTR(-EOPNOTSUPP);
> +	}

This is a hard error and should just be a WARN_ON_ONCE.

I'm also not sure we need the register time warnings at all.