Re: [PATCH v5 07/10] scsi: sd_zbc: emulate ZONE_APPEND commands

[Christoph Hellwig <hch@infradead.org>]

> +	spin_lock_bh(&sdkp->zones_wp_ofst_lock);
> +
> +	wp_ofst = sdkp->zones_wp_ofst[zno];
> +	if (wp_ofst == SD_ZBC_UPDATING_WP_OFST) {
> +		/* Write pointer offset update in progress: ask for a requeue */
> +		ret = BLK_STS_RESOURCE;
> +		goto err;
> +	}
> +
> +	if (wp_ofst == SD_ZBC_INVALID_WP_OFST) {
> +		/* Invalid write pointer offset: trigger an update from disk */
> +		ret = sd_zbc_update_wp_ofst(sdkp, zno);
> +		goto err;
> +	}

Maybe I'm a little too clever for my own sake, but what about something
like:

	spin_lock_bh(&sdkp->zones_wp_ofst_lock);
	switch (wp_ofst) {
	case SD_ZBC_INVALID_WP_OFST:
		if (scsi_device_get(sdkp->device)) {
			ret = BLK_STS_IOERR;
			break;
		}
		sdkp->zones_wp_ofst[zno] = SD_ZBC_UPDATING_WP_OFST;
		schedule_work(&sdkp->zone_wp_ofst_work);
		/*FALLTHRU*/
	case SD_ZBC_UPDATING_WP_OFST:
		ret = BLK_STS_DEV_RESOURCE;
		break;
	default:
		wp_ofst = sectors_to_logical(sdkp->device, wp_ofst);
		if (wp_ofst + nr_blocks > sdkp->zone_blocks) {
			ret = BLK_STS_IOERR;
			break;
		}

		*lba += wp_ofst;
	}
	spin_unlock_bh(&sdkp->zones_wp_ofst_lock);
	if (ret)
		blk_req_zone_write_unlock(rq);
	return ret;
}

>  	int result = cmd->result;
> @@ -294,7 +543,18 @@ void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
>  		 * so be quiet about the error.
>  		 */
>  		rq->rq_flags |= RQF_QUIET;
> +		goto unlock_zone;
>  	}
> +
> +	if (sd_zbc_need_zone_wp_update(rq))
> +		good_bytes = sd_zbc_zone_wp_update(cmd, good_bytes);
> +
> +
> +unlock_zone:

why not use a good old "else if" here?