Re: [PATCH v5 1/2] virtio-blk: support polling I/O

From: Christoph Hellwig <hch@infradead.org>
To: Suwan Kim <suwan.kim027@gmail.com>
Cc: mgurtovoy@nvidia.com, linux-block@vger.kernel.org,
	mst@redhat.com, virtualization@lists.linux-foundation.org,
	hch@infradead.org, stefanha@redhat.com, pbonzini@redhat.com
Subject: Re: [PATCH v5 1/2] virtio-blk: support polling I/O
Date: Tue, 5 Apr 2022 22:00:29 -0700	[thread overview]
Message-ID: <Yk0ebS3cl95XtOuj@infradead.org> (raw)
In-Reply-To: <20220405150924.147021-2-suwan.kim027@gmail.com>

On Wed, Apr 06, 2022 at 12:09:23AM +0900, Suwan Kim wrote:
> +        for (i = 0; i < num_vqs - num_poll_vqs; i++) {
> +                callbacks[i] = virtblk_done;
> +                snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
> +                names[i] = vblk->vqs[i].name;
> +        }
> +
> +        for (; i < num_vqs; i++) {
> +                callbacks[i] = NULL;
> +                snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
> +                names[i] = vblk->vqs[i].name;
> +        }

This uses spaces for indentation.

> +		/*
> +		 * Regular queues have interrupts and hence CPU affinity is
> +		 * defined by the core virtio code, but polling queues have
> +		 * no interrupts so we let the block layer assign CPU affinity.
> +		 */
> +		if (i != HCTX_TYPE_POLL)
> +			blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);
> +		else
> +			blk_mq_map_queues(&set->map[i]);

Nit, but I would have just done a "positive" check here as that is ab it
easier to read:

		if (i == HCTX_TYPE_POLL)
			blk_mq_map_queues(&set->map[i]);
		else
			blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
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