linux-kernel - Re: [PATCH 12/20] ublk: implement integrity user copy

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Message-ID: <aU31Ey2jWJi8U_53@fedora>
Date: Fri, 26 Dec 2025 10:38:11 +0800
From: Ming Lei <ming.lei@...hat.com>
To: Caleb Sander Mateos <csander@...estorage.com>
Cc: Jens Axboe <axboe@...nel.dk>, Shuah Khan <shuah@...nel.org>,
	linux-block@...r.kernel.org, linux-kselftest@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Stanley Zhang <stazhang@...estorage.com>,
	Uday Shankar <ushankar@...estorage.com>
Subject: Re: [PATCH 12/20] ublk: implement integrity user copy

On Tue, Dec 16, 2025 at 10:34:46PM -0700, Caleb Sander Mateos wrote:
> From: Stanley Zhang <stazhang@...estorage.com>
> 
> Add a function ublk_copy_user_integrity() to copy integrity information
> between a request and a user iov_iter. This mirrors the existing
> ublk_copy_user_pages() but operates on request integrity data instead of
> regular data. Check UBLKSRV_IO_INTEGRITY_FLAG in iocb->ki_pos in
> ublk_user_copy() to choose between copying data or integrity data.
> 
> Signed-off-by: Stanley Zhang <stazhang@...estorage.com>
> [csander: change offset units from data bytes to integrity data bytes,
>  test UBLKSRV_IO_INTEGRITY_FLAG after subtracting UBLKSRV_IO_BUF_OFFSET,
>  fix CONFIG_BLK_DEV_INTEGRITY=n build,
>  rebase on ublk user copy refactor]
> Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
> ---
>  drivers/block/ublk_drv.c | 43 ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 7fa0a9f0bfae..042df4de9253 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -606,10 +606,15 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
>  {
>  	return ((pos - UBLKSRV_IO_BUF_OFFSET) >> UBLK_TAG_OFF) &
>  		UBLK_TAG_BITS_MASK;
>  }
>  
> +static inline bool ublk_pos_is_integrity(loff_t pos)
> +{
> +	return !!((pos - UBLKSRV_IO_BUF_OFFSET) & UBLKSRV_IO_INTEGRITY_FLAG);
> +}
> +
>  static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>  {
>  	const struct ublk_param_basic *p = &ub->params.basic;
>  
>  	if (p->attrs & UBLK_ATTR_READ_ONLY)
> @@ -1034,10 +1039,31 @@ static size_t ublk_copy_user_pages(const struct request *req,
>  			break;
>  	}
>  	return done;
>  }
>  
> +static size_t ublk_copy_user_integrity(const struct request *req,
> +		unsigned offset, struct iov_iter *uiter, int dir)
> +{
> +	size_t done = 0;
> +#ifdef CONFIG_BLK_DEV_INTEGRITY
> +	struct bio *bio = req->bio;
> +	struct bvec_iter iter;
> +	struct bio_vec iv;
> +
> +	if (!blk_integrity_rq(req))
> +		return 0;
> +
> +	bio_for_each_integrity_vec(iv, bio, iter) {
> +		if (!ublk_copy_user_bvec(iv, &offset, uiter, dir, &done))
> +			break;
> +	}
> +#endif
> +
> +	return done;
> +}

The usual way is to define the whole helper conditionally:

#ifdef CONFIG_BLK_DEV_INTEGRITY
static size_t ublk_copy_user_integrity(const struct request *req,
		unsigned offset, struct iov_iter *uiter, int dir)
{
	...
}
#else
static inline size_t ublk_copy_user_integrity(const struct request *req,
		unsigned offset, struct iov_iter *uiter, int dir)
{
	return 0;
}
#endif

Otherwise, this patch looks fine.


Thanks, 
Ming