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

From: "Elliott, Robert (Servers)" <elliott@hpe.com>
To: 'Suwan Kim' <suwan.kim027@gmail.com>,
	"mst@redhat.com" <mst@redhat.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>,
	"stefanha@redhat.com" <stefanha@redhat.com>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"mgurtovoy@nvidia.com" <mgurtovoy@nvidia.com>,
	"dongli.zhang@oracle.com" <dongli.zhang@oracle.com>,
	"hch@infradead.org" <hch@infradead.org>
Cc: "virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: RE: [PATCH v5 1/2] virtio-blk: support polling I/O
Date: Wed, 6 Apr 2022 01:43:55 +0000	[thread overview]
Message-ID: <MW5PR84MB18421588C1806B6E37FCECAEABE79@MW5PR84MB1842.NAMPRD84.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20220405150924.147021-2-suwan.kim027@gmail.com>


> -----Original Message-----
> From: Suwan Kim <suwan.kim027@gmail.com>
> Sent: Tuesday, April 5, 2022 10:09 AM
> Subject: [PATCH v5 1/2] virtio-blk: support polling I/O
> 
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> @@ -81,6 +85,7 @@ struct virtio_blk {
> 
> 	/* num of vqs */
> 	int num_vqs;
> +	int io_queues[HCTX_MAX_TYPES];
>  	struct virtio_blk_vq *vqs;
...
>  };> @@ -565,6 +572,18 @@ static int init_vq(struct virtio_blk *vblk)
>  			min_not_zero(num_request_queues, nr_cpu_ids),
>  			num_vqs);
> 
> +	num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
> +
> +	memset(vblk->io_queues, 0, sizeof(int) * HCTX_MAX_TYPES);

Using
    sizeof(vblk->io_queues)
would automatically follow any changes in the definition of that field,
similar to the line below:

...
>  	vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);