Messages in this thread Patch in this message | | | From | Mihail Atanassov <> | Subject | [PATCH] drm: Add helper macro for duplicating custom drm_*_state | Date | Thu, 9 Feb 2017 15:41:42 +0000 |
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Assuming a derived struct of the form:
struct foo_bar_state { struct drm_bar_state bar_state; struct foo_private priv; struct foo_private2 *priv2; };
memcpy priv and priv2 to the new instance of foo_bar_state. The intention is to use this macro in ->atomic_duplicate_state in conjunction with __drm_atomic_helper_*_duplicate_state, which already copies the relevant drm_*_state struct.
There's an equality check for new_state and old_state to ensure that they are distinct instances of the same type, and a BUILD_BUG if the base struct (bar_state in the above example) is not first in the derived struct, to avoid missing any data before it and corrupting the base's data.
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com> --- include/drm/drm_atomic_helper.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h index d066e94..ecc6a82 100644 --- a/include/drm/drm_atomic_helper.h +++ b/include/drm/drm_atomic_helper.h @@ -171,6 +171,39 @@ int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc, uint32_t size); /** + * drm_atomic_duplicate_custom_state - helper macro for duplicating + * driver-private additions to drm_*_state. + * @new_state: pointer to destination state struct + * @old_state: pointer to source state struct + * @basename: name of the drm_*_state member of the new_state/old_state struct + * + * Copies the data after the base struct until the end of the custom struct, + * e.g. given a structure + * + * struct foo_bar_state { + * struct drm_bar_state base; + * struct foo_private priv; + * struct foo_private2 *priv2; + * }; + * + * this copies priv and priv2. NB: the base struct *must* be the first element + * of the derived struct, and new_state and old_state have to be two distinct + * instances. + */ +#define drm_atomic_helper_duplicate_custom_state(new_state, old_state, basename) \ + do { \ + size_t base_size = sizeof(new_state->basename); \ + size_t base_offset = offsetof(typeof(*new_state), basename); \ + \ + BUILD_BUG_ON(base_offset != 0); \ + if (new_state == old_state) /* Type-check */ \ + break; \ + memcpy((char *)new_state + base_size, \ + (char *)old_state + base_size, \ + sizeof(*new_state) - base_size); \ + } while(0) + +/** * drm_atomic_crtc_for_each_plane - iterate over planes currently attached to CRTC * @plane: the loop cursor * @crtc: the crtc whose planes are iterated -- 1.9.1
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