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

["Andreas Hindborg (Samsung)" <nmi@metaspace.dk>]

Ming Lei <ming.lei@redhat.com> writes:

> On Wed, Jun 28, 2023 at 09:06:49PM +0200, Andreas Hindborg wrote:
>> From: Andreas Hindborg <a.hindborg@samsung.com>
>> 
>> 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.

I will squash the patches and reject zone support if not user copy is
enabled 👍

>
>> 
>> Suggested-by: Ming Lei <ming.lei@redhat.com>
>> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
>> ---
>>  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?

It needs to go before the call to `ublk_revalidate_disk_zones()` because
that does IO to the disk in the form of a call to `report_zones()`. So I
can move it down a little bit.

Best regards,
Andreas