Re: [Xen-devel] [PATCH v4 02/13] libxl: add generic functions to get and free device list

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Tue, Jul 18, 2017 at 05:25:19PM +0300, Oleksandr Grytsov wrote:
> From: Oleksandr Grytsov <oleksandr_grytsov@xxxxxxxx>
> 
> Add libxl__device_list and libxl__device_list_free
> functions to handle device list using the device
> framework.
> 
> Signed-off-by: Oleksandr Grytsov <oleksandr_grytsov@xxxxxxxx>
> ---
>  tools/libxl/libxl_device.c   | 66 
> ++++++++++++++++++++++++++++++++++++++++++++
>  tools/libxl/libxl_internal.h |  8 ++++++
>  2 files changed, 74 insertions(+)
> 
> diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
> index 07165f0..f1d4848 100644
> --- a/tools/libxl/libxl_device.c
> +++ b/tools/libxl/libxl_device.c
> @@ -1991,6 +1991,72 @@ out:
>      return rc;
>  }
>  
> +void *libxl__device_list(libxl__gc *gc, const struct libxl_device_type *dt,
> +                         uint32_t domid, const char* name, int *num)
> +{
> +    void *r = NULL;
> +    void *list = NULL;
> +    void *item = NULL;
> +    char *libxl_path;
> +    char **dir = NULL;
> +    unsigned int ndirs = 0;
> +    int rc;
> +
> +    *num = 0;
> +
> +    libxl_path = GCSPRINTF("%s/device/%s",
> +                           libxl__xs_libxl_path(gc, domid), name);
> +
> +    dir = libxl__xs_directory(gc, XBT_NULL, libxl_path, &ndirs);
> +
> +    if (dir && ndirs) {
> +        list = libxl__malloc(NOGC, dt->dev_elem_size * ndirs);
> +        void *end = (uint8_t *)list + ndirs * dt->dev_elem_size;
> +        item = list;
> +
> +        while (item < end) {
> +            dt->init(item);
> +
> +            if (dt->from_xenstore) {
> +                char* device_libxl_path = GCSPRINTF("%s/%s", libxl_path, 
> *dir);
> +                rc = dt->from_xenstore(gc, device_libxl_path, atoi(*dir), 
> item);
> +                if (rc) goto out;
> +            }
> +
> +            item = (uint8_t*)item + dt->dev_elem_size;

Space before *.

> +            ++dir;
> +        }
> +    }
> +
> +    *num = ndirs;
> +    r = list;
> +    list = NULL;
> +
> +out:
> +
> +    if (list) {
> +        *num = 0;
> +        while(item >= list) {

Space after while, but ...

> +            dt->dispose(item);
> +            item = (uint8_t*)item - dt->dev_elem_size;
> +        }
> +        free(list);

You should be able to use libxl__device_list_free here.

> +    }
> +
> +    return r;
> +}
> +
> +void libxl__device_list_free(const struct libxl_device_type *dt,
> +                             void *list, int num)
> +{
> +    int i;
> +
> +    for (i = 0; i < num; i++)
> +        dt->dispose((uint8_t*)list + i * dt->dev_elem_size);
> +
> +    free(list);
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> index 075dfe3..271ac89 100644
> --- a/tools/libxl/libxl_internal.h
> +++ b/tools/libxl/libxl_internal.h
> @@ -3506,6 +3506,7 @@ struct libxl_device_type {
>      int (*dm_needed)(void *, unsigned);
>      void (*update_config)(libxl__gc *, void *, void *);
>      int (*update_devid)(libxl__gc *, uint32_t, void *);
> +    int (*from_xenstore)(libxl__gc *, const char *, libxl_devid, void *);
>      int (*set_xenstore_config)(libxl__gc *, uint32_t, void *, flexarray_t *,
>                                 flexarray_t *, flexarray_t *);
>  };
> @@ -4386,6 +4387,13 @@ void libxl__device_add_async(libxl__egc *egc, uint32_t 
> domid,
>  int libxl__device_add(libxl__gc *gc, uint32_t domid,
>                        const struct libxl_device_type *dt, void *type);
>  
> +/* Caller is responsible for freeing the memory by calling
> + * libxl__device_list_free
> + */
> +void* libxl__device_list(libxl__gc *gc, const struct libxl_device_type *dt,
> +                         uint32_t domid, const char* name, int *num);
> +void libxl__device_list_free(const struct libxl_device_type *dt,
> +                             void *list, int num);
>  #endif
>  
>  /*
> -- 
> 2.7.4
> 

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