Re: [PATCH] scsi: virtio_scsi: Use struct_size() helper

From: Stefan Hajnoczi <stefanha@redhat.com>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	virtualization@lists.linux-foundation.org,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] scsi: virtio_scsi: Use struct_size() helper
Date: Mon, 1 Jul 2019 16:21:48 +0100	[thread overview]
Message-ID: <20190701152148.GG11900@stefanha-x1.localdomain> (raw)
In-Reply-To: <20190619192833.GA825@embeddedor>

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On Wed, Jun 19, 2019 at 02:28:33PM -0500, Gustavo A. R. Silva wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
> 
> struct virtio_scsi {
> 	...
>         struct virtio_scsi_vq req_vqs[];
> };
> 
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
> 
> So, replace the following form:
> 
> sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues
> 
> with:
> 
> struct_size(vscsi, req_vqs, num_queues)
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
>  drivers/scsi/virtio_scsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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