Re: [PATCH 1/2] scsi: ufs: Add Multi-Circular Queue support

From: Bart Van Assche <bvanassche@acm.org>
To: Can Guo <quic_cang@quicinc.com>,
	stanley.chu@mediatek.com, adrian.hunter@intel.com,
	alim.akhtar@samsung.com, avri.altman@wdc.com, beanhuo@micron.com,
	quic_asutoshd@quicinc.com, quic_nguyenb@quicinc.com,
	quic_ziqichen@quicinc.com, linux-scsi@vger.kernel.org,
	kernel-team@android.com
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Daejun Park <daejun7.park@samsung.com>,
	Jinyoung Choi <j-young.choi@samsung.com>,
	Kiwoong Kim <kwmad.kim@samsung.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] scsi: ufs: Add Multi-Circular Queue support
Date: Thu, 28 Jul 2022 12:38:14 -0700	[thread overview]
Message-ID: <f803e7fb-9dde-e4d4-a55c-6427516dfdbb@acm.org> (raw)
In-Reply-To: <1658214120-22772-2-git-send-email-quic_cang@quicinc.com>

On 7/19/22 00:01, Can Guo wrote:
>   static int ufshcd_map_queues(struct Scsi_Host *shost)
>   {
> -	int i, ret;
> +	int i, queue_offset = 0, ret;
> +	struct ufs_hba *hba = shost_priv(shost);
>   
>   	for (i = 0; i < shost->nr_maps; i++) {
>   		struct blk_mq_queue_map *map = &shost->tag_set.map[i];
>   
> -		switch (i) {
> -		case HCTX_TYPE_DEFAULT:
> -		case HCTX_TYPE_POLL:
> -			map->nr_queues = 1;
> -			break;
> -		case HCTX_TYPE_READ:
> -			map->nr_queues = 0;
> +		map->nr_queues = hba->nr_queues[i];
> +		if (!map->nr_queues)
>   			continue;
> -		default:
> -			WARN_ON_ONCE(true);
> -		}
> -		map->queue_offset = 0;
> +
> +		map->queue_offset = queue_offset;
> +		if (i == HCTX_TYPE_POLL && !is_mcq_enabled(hba))
> +			map->queue_offset = 0;
> +
>   		ret = blk_mq_map_queues(map);
> -		WARN_ON_ONCE(ret);
> +
> +		if (ret)
> +			return ret;
> +
> +		queue_offset += map->nr_queues;
>   	}

It is not clear to me why the WARN_ON_ONCE(ret) statement has been 
changed into "if (ret) return ret;"?

Thanks,

Bart.