Re: [Qemu-devel] [PATCH for-2.12] hw/rdma: fix clang compilation errors

[Eric Blake]

On 03/21/2018 07:40 AM, Marcel Apfelbaum wrote:
> Fix some enum castings and extra parentheses.
>
> Reported-by: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Marcel Apfelbaum <address@hidden>
> ---
>   hw/rdma/vmw/pvrdma_cmd.c  | 5 +++--
>   hw/rdma/vmw/pvrdma_main.c | 5 +++--
>   2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
> index 293dfed29f..25f747a190 100644
> --- a/hw/rdma/vmw/pvrdma_cmd.c
> +++ b/hw/rdma/vmw/pvrdma_cmd.c
> @@ -73,7 +73,7 @@ static void *pvrdma_map_to_pdir(PCIDevice *pdev, uint64_t 
> pdir_dma,
>       tbl_idx = 1;
>       addr_idx = 1;
>       while (addr_idx < nchunks) {
> -        if ((tbl_idx == (TARGET_PAGE_SIZE / sizeof(uint64_t)))) {
> +        if (tbl_idx == (TARGET_PAGE_SIZE / sizeof(uint64_t))) {

Can't you still simplify that further to

if (tbl_idx == TARGET_PAGE_SIZE / sizeof(uint64_t)) {

> @@ -292,7 +292,8 @@ static void init_ports(PVRDMADev *dev, Error **errp)
>       memset(dev->rdma_dev_res.ports, 0, sizeof(dev->rdma_dev_res.ports));
>   
>       for (i = 0; i < MAX_PORTS; i++) {
> -        dev->rdma_dev_res.ports[i].state = PVRDMA_PORT_DOWN;
> +        dev->rdma_dev_res.ports[i].state =
> +            (enum ibv_port_state)PVRDMA_PORT_DOWN;
>   

This one looks suspicious - shouldn't you instead be using IBV_PORT_DOWN 
instead of having to cast?  (Even if IBV_PORT_DOWN and PVRDMA_PORT_DOWN 
both have the value of 1 for now, the compiler warning is telling you 
that either one of the two enums can change independently in the future, 
and using a cast to shut up the compiler feels unsafe).

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org