Re: [PATCH v4 4/4] ublk: add zone append

[Ming Lei]

On Wed, Jun 28, 2023 at 09:06:49PM +0200, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> 
> Add zone append feature to ublk. This feature uses the `addr` field of `struct
> ublksrv_io_cmd`. Therefore ublk must be used with the user copy
> feature (UBLK_F_USER_COPY) for zone append to be available. Without this
> feature, ublk will fail zone append requests.

Given zone append is a must, please fail to add device in case of zoned
and !user_copy, then we can make fast IO code path clean.

> 
> Suggested-by: Ming Lei <ming.lei@xxxxxxxxxx>
> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> ---
>  drivers/block/ublk_drv-zoned.c | 11 +++++++++
>  drivers/block/ublk_drv.c       | 43 ++++++++++++++++++++++++++++++----
>  drivers/block/ublk_drv.h       |  1 +
>  include/uapi/linux/ublk_cmd.h  |  3 ++-
>  4 files changed, 52 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/block/ublk_drv-zoned.c b/drivers/block/ublk_drv-zoned.c
> index ea86bf4b3681..007e8fc7ff25 100644
> --- a/drivers/block/ublk_drv-zoned.c
> +++ b/drivers/block/ublk_drv-zoned.c
> @@ -16,6 +16,16 @@ void ublk_set_nr_zones(struct ublk_device *ub)
>  		ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
>  }
>  
> +int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> +{
> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> +
> +	if (! p->max_zone_append_sectors)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  void ublk_dev_param_zoned_apply(struct ublk_device *ub)
>  {
>  	const struct ublk_param_zoned *p = &ub->params.zoned;
> @@ -23,6 +33,7 @@ void ublk_dev_param_zoned_apply(struct ublk_device *ub)
>  	if (ub->dev_info.flags & UBLK_F_ZONED) {
>  		disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
>  		disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
> +		blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
>  	}
>  }
>  
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 88fa39853c61..6a949669b47e 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -107,6 +107,11 @@ struct ublk_uring_cmd_pdu {
>   */
>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
>  
> +/*
> + * Set when IO is Zone Append
> + */
> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
> +
>  struct ublk_io {
>  	/* userspace buffer address from io cmd */
>  	__u64	addr;
> @@ -230,6 +235,8 @@ static void ublk_dev_param_discard_apply(struct ublk_device *ub)
>  
>  static int ublk_validate_params(const struct ublk_device *ub)
>  {
> +	int ret = 0;
> +
>  	/* basic param is the only one which must be set */
>  	if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
>  		const struct ublk_param_basic *p = &ub->params.basic;
> @@ -260,6 +267,13 @@ static int ublk_validate_params(const struct ublk_device *ub)
>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>  		return -EINVAL;
>  
> +	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
> +	    (ub->params.types & UBLK_PARAM_TYPE_ZONED)) {
> +		ret = ublk_dev_param_zoned_validate(ub);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -690,6 +704,11 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>  			return BLK_STS_IOERR;
>  		}
>  	case REQ_OP_ZONE_APPEND:
> +		if (!(ubq->dev->dev_info.flags & UBLK_F_USER_COPY))
> +			return BLK_STS_IOERR;
> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
> +		break;
>  	case REQ_OP_ZONE_RESET_ALL:
>  	case REQ_OP_DRV_OUT:
>  		/* We do not support zone append or reset_all yet */
> @@ -1112,6 +1131,12 @@ static void ublk_commit_completion(struct ublk_device *ub,
>  	/* find the io request and complete */
>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
>  
> +	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED)) {
> +		if (io->flags & UBLK_IO_FLAG_ZONE_APPEND)
> +			req->__sector = ub_cmd->addr;
> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
> +	}
> +
>  	if (req && likely(!blk_should_fake_timeout(req->q)))
>  		ublk_put_req_ref(ubq, req);
>  }
> @@ -1411,7 +1436,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
>  		goto out;
>  
> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
> +	if (ublk_support_user_copy(ubq) &&
> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
>  		ret = -EINVAL;
>  		goto out;
>  	}
> @@ -1534,11 +1560,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
>  		int ubuf_dir)
>  {
>  	/* copy ubuf to request pages */
> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
> +	    ubuf_dir == ITER_SOURCE)
>  		return true;
>  
>  	/* copy request pages to ubuf */
> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
> +	if ((req_op(req) == REQ_OP_WRITE ||
> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
> +	    ubuf_dir == ITER_DEST)
>  		return true;
>  
>  	return false;
> @@ -1867,6 +1896,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>  	ub->dev_info.ublksrv_pid = ublksrv_pid;
>  	ub->ub_disk = disk;
>  
> +	ub->dev_info.state = UBLK_S_DEV_LIVE;

I guess the above line change isn't necessary?


Thanks, 
Ming