Re: [Xen-devel] [PATCH v6 04/11] libxl: ocaml: allow device operations to be called asynchronously

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-12-09 at 15:17 +0000, Rob Hoes wrote:
> Signed-off-by: Rob Hoes <rob.hoes@xxxxxxxxxx>
> CC: David Scott <dave.scott@xxxxxxxxxxxxx>
> CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
> 
> ---
> v6: Updated patch to register for_callback value with the GC.
> ---
>  tools/ocaml/libs/xl/genwrap.py       |    6 +++---
>  tools/ocaml/libs/xl/xenlight_stubs.c |   18 +++++++++++++++---
>  2 files changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/ocaml/libs/xl/genwrap.py b/tools/ocaml/libs/xl/genwrap.py
> index f5d2224..dd43069 100644
> --- a/tools/ocaml/libs/xl/genwrap.py
> +++ b/tools/ocaml/libs/xl/genwrap.py
> @@ -22,9 +22,9 @@ builtins = {
>      "libxl_cpuid_policy_list": ("unit",                "%(c)s = 0",          
>                "Val_unit"),
>      }
>  
> -DEVICE_FUNCTIONS = [ ("add",            ["ctx", "t", "domid", "unit"]),
> -                     ("remove",         ["ctx", "t", "domid", "unit"]),
> -                     ("destroy",        ["ctx", "t", "domid", "unit"]),
> +DEVICE_FUNCTIONS = [ ("add",            ["ctx", "t", "domid", "?async:'a", 
> "unit", "unit"]),
> +                     ("remove",         ["ctx", "t", "domid", "?async:'a", 
> "unit", "unit"]),
> +                     ("destroy",        ["ctx", "t", "domid", "?async:'a", 
> "unit", "unit"]),
>                     ]
>  
>  functions = { # ( name , [type1,type2,....] )
> diff --git a/tools/ocaml/libs/xl/xenlight_stubs.c 
> b/tools/ocaml/libs/xl/xenlight_stubs.c
> index 660dd09..b6649a7 100644
> --- a/tools/ocaml/libs/xl/xenlight_stubs.c
> +++ b/tools/ocaml/libs/xl/xenlight_stubs.c
> @@ -401,15 +401,27 @@ void async_callback(libxl_ctx *ctx, int rc, void 
> *for_callback)
>  #define STRINGIFY(x) _STRINGIFY(x)
>  
>  #define _DEVICE_ADDREMOVE(type,op)                                   \
> -value stub_xl_device_##type##_##op(value ctx, value info, value domid)       
> \
> +value stub_xl_device_##type##_##op(value ctx, value info, value domid,       
> \
> +     value async, value unit)                                        \
>  {                                                                    \
> -     CAMLparam3(ctx, info, domid);                                   \
> +     CAMLparam5(ctx, info, domid, async, unit);                      \
>       libxl_device_##type c_info;                                     \
>       int ret, marker_var;                                            \
> +     libxl_asyncop_how ao_how;                                       \
> +     value *p;                                                       \
>                                                                       \
>       device_##type##_val(CTX, &c_info, info);                        \
>                                                                       \
> -     ret = libxl_device_##type##_##op(CTX, Int_val(domid), &c_info, 0); \
> +     if (async != Val_none) {                                        \
> +             p = malloc(sizeof(value));                              \

This lacks error handling, or as Ian J suggested previously a wrapper to
fail in a graceful manner. I think that can be a future more global
cleanup though.

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

> +             *p = Some_val(async);                                   \
> +             caml_register_global_root(p);                           \
> +             ao_how.callback = async_callback;                       \
> +             ao_how.u.for_callback = (void *) p;                     \
> +     }                                                               \
> +                                                                     \
> +     ret = libxl_device_##type##_##op(CTX, Int_val(domid), &c_info,  \
> +             async != Val_none ? &ao_how : NULL);                    \
>                                                                       \
>       libxl_device_##type##_dispose(&c_info);                         \
>                                                                       \



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel