Re: [PATCH 08/26] IB/ocrdma: Improve size determinations in ocrdma_mbx_rdma_stats()

Yuval Shaia
2017-03-08T14:22:57Z

On Wed, Mar 08, 2017 at 01:58:49PM +0100, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Tue, 7 Mar 2017 20:16:16 +0100
>
> Replace the specification of two data structures by pointer dereferences
> as the parameter for the operator "sizeof" to make the corresponding size
> determinations a bit safer according to the Linux coding style convention.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> drivers/infiniband/hw/ocrdma/ocrdma_hw.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_hw.c b/drivers/infiniband/hw/ocrdma/ocrdma_hw.c
> index 1f7d88d7569e..0628600bee56 100644
> --- a/drivers/infiniband/hw/ocrdma/ocrdma_hw.c
> +++ b/drivers/infiniband/hw/ocrdma/ocrdma_hw.c
> @@ -1302,7 +1302,7 @@ int ocrdma_mbx_rdma_stats(struct ocrdma_dev *dev, bool reset)
> mqe->u.nonemb_req.sge[0].len = dev->stats_mem.size;
>
> /* Cache the old stats */
> - memcpy(old_stats, req, sizeof(struct ocrdma_rdma_stats_resp));
> + memcpy(old_stats, req, sizeof(*old_stats));

Isn't sizeof(req) smaller than sizeof(*old_stats)?

> memset(req, 0, dev->stats_mem.size);
>
> ocrdma_init_mch((struct ocrdma_mbx_hdr *)req,
> @@ -1315,7 +1315,7 @@ int ocrdma_mbx_rdma_stats(struct ocrdma_dev *dev, bool reset)
> status = ocrdma_nonemb_mbx_cmd(dev, mqe, dev->stats_mem.va);
> if (status)
> /* Copy from cache, if mbox fails */
> - memcpy(req, old_stats, sizeof(struct ocrdma_rdma_stats_resp));
> + memcpy(req, old_stats, sizeof(*old_stats));

Fix itself looks fine but original code seems strange and makes me anxious
since resp is (much) bigger than req.

> else
> ocrdma_le32_to_cpu(req, dev->stats_mem.size);
>
> --
> 2.12.0
>
> --
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