On Mar 29, 2019, at 8:23 AM, Bob Liu <bob.liu@oracle.com> wrote:
> 
> This patch adds a function verifier callback to submit_bio.  The
> filesystem layer can use submit_bio_verify to pass a call back
> to the block layer which can then be used to verify if the data
> read is correct.

How does this interact (if at all) with bio_integrity_verify() code?
Does it mean if e.g. XFS is on storage with T10-PI that only one or
the other can be used, or will it be possible to chain the verify
callbacks?

Cheers, Andreas

> Signed-off-by: Bob Liu <bob.liu@oracle.com>
> ---
> block/blk-core.c    | 13 ++++++++++---
> include/linux/bio.h |  2 ++
> 2 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 6b78ec56a4f2..d265d2924c32 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1156,15 +1156,16 @@ blk_qc_t direct_make_request(struct bio *bio)
> EXPORT_SYMBOL_GPL(direct_make_request);
> 
> /**
> - * submit_bio - submit a bio to the block device layer for I/O
> + * submit_bio_verify - submit a bio to the block device layer for I/O
>  * @bio: The &struct bio which describes the I/O
>  *
> - * submit_bio() is very similar in purpose to generic_make_request(), and
> + * submit_bio_verify() is very similar in purpose to generic_make_request(), and
>  * uses that function to do most of the work. Both are fairly rough
>  * interfaces; @bio must be presetup and ready for I/O.
>  *
>  */
> -blk_qc_t submit_bio(struct bio *bio)
> +blk_qc_t submit_bio_verify(struct bio *bio,
> +		int (*verifier_cb_func)(struct bio *))
> {
> 	/*
> 	 * If it's a regular read/write or a barrier with data attached,
> @@ -1197,6 +1198,12 @@ blk_qc_t submit_bio(struct bio *bio)
> 
> 	return generic_make_request(bio);
> }
> +EXPORT_SYMBOL(submit_bio_verify);
> +
> +blk_qc_t submit_bio(struct bio *bio)
> +{
> +	return submit_bio_verify(bio, NULL);
> +}
> EXPORT_SYMBOL(submit_bio);
> 
> /**
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index 7380b094dcca..ddaadab74dcf 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -398,6 +398,8 @@ static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
> 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
> }
> 
> +extern blk_qc_t submit_bio_verify(struct bio *,
> +		int (*verifier_cb_func)(struct bio *));
> extern blk_qc_t submit_bio(struct bio *);
> 
> extern void bio_endio(struct bio *);
> --
> 2.17.1
> 


Cheers, Andreas