Re: [PATCH V4 22/24] xl: update domain configuration when we hotplug a device

[David Vrabel <david.vrabel@citrix.com>]

On 01/05/14 13:58, Wei Liu wrote:
> A convenient macro is written to accomplish following tasks:
> 
> 1. load domain configuration
> 2. allocate a new device structure NEW
> 3. copy the parsed device strcture PARSED to NEW
> 4. call libxl_device_TYPE_add(PARSED)
> 5. pull from PARSED any fields that might be touched by libxl to NEW
> 6. store domain configuration
> 
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> ---
>  tools/libxl/xl_cmdimpl.c |   85 +++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 69 insertions(+), 16 deletions(-)
> 
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index 83f058e..91172c5 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -381,6 +381,36 @@ static void *xrealloc(void *ptr, size_t sz) {
>          &(array)[array_extend_old_count];                               \
>      })
>  
> +#define ARRAY_EXTEND_INIT_NODEVID(array,count,initfn)                   \
> +    ({                                                                  \
> +        typeof((count)) array_extend_old_count = (count);               \
> +        (count)++;                                                      \
> +        (array) = xrealloc((array), sizeof(*array) * (count));          \
> +        (initfn)(&(array)[array_extend_old_count]);                     \
> +        &(array)[array_extend_old_count];                               \
> +    })
> +
> +/* Add a device and update the stored configuration */
> +#define ADD_DEVICE(devtype,domid,dev,d_config,ptr,allocate,maybe_fixup) \
> +    do {                                                                \
> +        libxl_domain_config_init((d_config));                           \
> +        load_domain_config((domid), (d_config));                        \
> +                                                                        \
> +        allocate;                                                       \
> +                                                                        \
> +        libxl_device_ ## devtype ## _copy(ctx,(ptr),&(dev));            \
> +                                                                        \
> +        if (libxl_device_ ## devtype ## _add(ctx,(domid),&(dev), 0)) {  \
> +            fprintf(stderr, "libxl_device_%s_add failed.\n", #devtype); \
> +            exit(1);                                                    \
> +        }                                                               \
> +                                                                        \
> +        maybe_fixup;                                                    \
> +                                                                        \
> +        store_domain_config((domid), (d_config));                       \
> +        libxl_domain_config_dispose((d_config));                        \
> +    } while (0)
> +

Is there a better way of doing this without these obtuse macros?

Is libxl lacking is a proper device abstraction layer?

David