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Date:   Fri, 17 Jun 2022 09:33:11 -0700
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Subject: Re: [PATCH 5/5] blk-mq: Drop 'reserved' member of busy_tag_iter_fn
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To:     John Garry <john.garry@huawei.com>, axboe@kernel.dk,
        damien.lemoal@opensource.wdc.com, hch@lst.de, jejb@linux.ibm.com,
        martin.petersen@oracle.com, hare@suse.de, satishkh@cisco.com,
        sebaddel@cisco.com, kartilak@cisco.com
Cc:     linux-rdma@vger.kernel.org, linux-mmc@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-s390@vger.kernel.org,
        linux-scsi@vger.kernel.org, mpi3mr-linuxdrv.pdl@broadcom.com,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        nbd@other.debian.org
References: <1655463320-241202-1-git-send-email-john.garry@huawei.com>
 <1655463320-241202-6-git-send-email-john.garry@huawei.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <1655463320-241202-6-git-send-email-john.garry@huawei.com>
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On 6/17/22 03:55, John Garry wrote:
> We no longer use the 'reserved' member in for any iter function so it
                                          ^^^^^^
One of these two words probably should be removed.

> diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
> index 2dcd738c6952..b8cc8b41553f 100644
> --- a/block/blk-mq-tag.c
> +++ b/block/blk-mq-tag.c
> @@ -266,7 +266,6 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
>   	struct blk_mq_hw_ctx *hctx = iter_data->hctx;
>   	struct request_queue *q = iter_data->q;
>   	struct blk_mq_tag_set *set = q->tag_set;
> -	bool reserved = iter_data->reserved;
>   	struct blk_mq_tags *tags;
>   	struct request *rq;
>   	bool ret = true;
> @@ -276,7 +275,7 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
>   	else
>   		tags = hctx->tags;
>   
> -	if (!reserved)
> +	if (!iter_data->reserved)
>   		bitnr += tags->nr_reserved_tags;
>   	/*
>   	 * We can hit rq == NULL here, because the tagging functions

Is the above change really necessary?

> @@ -337,12 +336,11 @@ static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
>   {
>   	struct bt_tags_iter_data *iter_data = data;
>   	struct blk_mq_tags *tags = iter_data->tags;
> -	bool reserved = iter_data->flags & BT_TAG_ITER_RESERVED;
>   	struct request *rq;
>   	bool ret = true;
>   	bool iter_static_rqs = !!(iter_data->flags & BT_TAG_ITER_STATIC_RQS);
>   
> -	if (!reserved)
> +	if (!(iter_data->flags & BT_TAG_ITER_RESERVED))
>   		bitnr += tags->nr_reserved_tags;
>   
>   	/*

Same question here: is the above change really necessary?

Thanks,

Bart.