Re: [igt-dev] [PATCH i-g-t v3 1/4] lib/ioctl_wrapper: use defines for get_param instead of param number

Daniele Ceraolo Spurio
2019-01-11T17:54:58Z

On 01/11/2019 08:15 AM, Lukasz Kalamarz wrote:
> In lib code there were few functions using param number instead of
> defines. This could lead to some issues (i.e. stolen support
> pointing on different parameter) and we would like to avoid them.

The 3 defines you're touching are part of the published kernel uapi, so
there is no way for them to change and cause issues. The change is still
worth doing IMO since defines are better than hard-coded numbers.

> v2: Rebased patch
>
> Signed-off-by: Lukasz Kalamarz <lukasz.kalamarz@intel.com>
> Cc: Michal Winiarski <michal.winiarski@intel.com>
> Cc: Katarzyna Dec <katarzyna.dec@intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>

All 3 defs are in the i915_drm.h file in IGT, so with a cleaned commit
message:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

> ---
> lib/ioctl_wrappers.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
> index 9f255508..f71f0e32 100644
> --- a/lib/ioctl_wrappers.c
> +++ b/lib/ioctl_wrappers.c
> @@ -708,12 +708,12 @@ bool gem_mmap__has_wc(int fd)
> has_wc = 0;
>
> memset(&gp, 0, sizeof(gp));
> - gp.param = 40; /* MMAP_GTT_VERSION */
> + gp.param = I915_PARAM_MMAP_GTT_VERSION;
> gp.value = &gtt_version;
> ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp);
>
> memset(&gp, 0, sizeof(gp));
> - gp.param = 30; /* MMAP_VERSION */
> + gp.param = I915_PARAM_MMAP_VERSION;
> gp.value = &mmap_version;
> ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp);
>
> @@ -964,7 +964,7 @@ static int gem_gtt_type(int fd)
> int val = 0;
>
> memset(&gp, 0, sizeof(gp));
> - gp.param = 18; /* HAS_ALIASING_PPGTT */
> + gp.param = I915_PARAM_HAS_ALIASING_PPGTT;
> gp.value = &val;
>
> if (ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp, sizeof(gp)))