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 <[email protected]>
---
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 <[email protected]>
> ---
> drivers/scsi/virtio_scsi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Stefan Hajnoczi <[email protected]>
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
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