Gustavo A. R. Silva
2019-Jun-19 19:28 UTC
[PATCH] scsi: virtio_scsi: Use struct_size() helper
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 at embeddedor.com> --- drivers/scsi/virtio_scsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 13f1b3b9923a..ed4f79bffc73 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -795,7 +795,7 @@ static int virtscsi_probe(struct virtio_device *vdev) num_targets = virtscsi_config_get(vdev, max_target) + 1; shost = scsi_host_alloc(&virtscsi_host_template, - sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues); + struct_size(vscsi, req_vqs, num_queues)); if (!shost) return -ENOMEM; -- 2.21.0
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 at embeddedor.com> > --- > drivers/scsi/virtio_scsi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)Reviewed-by: Stefan Hajnoczi <stefanha at redhat.com> -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20190701/7b122c4f/attachment.sig>
Martin K. Petersen
2019-Jul-12 00:18 UTC
[PATCH] scsi: virtio_scsi: Use struct_size() helper
Gustavo,> 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:Applied to 5.4/scsi-queue, thanks! -- Martin K. Petersen Oracle Linux Engineering
Michael S. Tsirkin
2019-Jul-12 14:14 UTC
[PATCH] scsi: virtio_scsi: Use struct_size() helper
On Thu, Jul 11, 2019 at 08:18:54PM -0400, Martin K. Petersen wrote:> > Gustavo, > > > 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: > > Applied to 5.4/scsi-queue, thanks!Oh I put it in the virtio tree already. Can't hurt I guess :)> -- > Martin K. Petersen Oracle Linux Engineering
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