| Message ID | 20220218100403.7028-17-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Review of mode copies | expand |
On 18/02/2022 12:03, Ville Syrjala wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > struct drm_display_mode embeds a list head, so overwriting > the full struct with another one will corrupt the list > (if the destination mode is on a list). Use drm_mode_copy() > instead which explicitly preserves the list head of > the destination mode. > > Even if we know the destination mode is not on any list > using drm_mode_copy() seems decent as it sets a good > example. Bad examples of not using it might eventually > get copied into code where preserving the list head > actually matters. > > Obviously one case not covered here is when the mode > itself is embedded in a larger structure and the whole > structure is copied. But if we are careful when copying > into modes embedded in structures I think we can be a > little more reassured that bogus list heads haven't been > propagated in. > > @is_mode_copy@ > @@ > drm_mode_copy(...) > { > ... > } > > @depends on !is_mode_copy@ > struct drm_display_mode *mode; > expression E, S; > @@ > ( > - *mode = E > + drm_mode_copy(mode, &E) > | > - memcpy(mode, E, S) > + drm_mode_copy(mode, E) > ) > > @depends on !is_mode_copy@ > struct drm_display_mode mode; > expression E; > @@ > ( > - mode = E > + drm_mode_copy(&mode, &E) > | > - memcpy(&mode, E, S) > + drm_mode_copy(&mode, E) > ) > > @@ > struct drm_display_mode *mode; > @@ > - &*mode > + mode > > Cc: Jyri Sarha <jyri.sarha@iki.fi> > Cc: Tomi Valkeinen <tomba@kernel.org> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c > index 29890d704cb4..853c6b443fff 100644 > --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c > +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c > @@ -433,7 +433,7 @@ static void tilcdc_crtc_set_mode(struct drm_crtc *crtc) > > set_scanout(crtc, fb); > > - crtc->hwmode = crtc->state->adjusted_mode; > + drm_mode_copy(&crtc->hwmode, &crtc->state->adjusted_mode); > > tilcdc_crtc->hvtotal_us = > tilcdc_mode_hvtotal(&crtc->hwmode); Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Tomi
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c index 29890d704cb4..853c6b443fff 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c @@ -433,7 +433,7 @@ static void tilcdc_crtc_set_mode(struct drm_crtc *crtc) set_scanout(crtc, fb); - crtc->hwmode = crtc->state->adjusted_mode; + drm_mode_copy(&crtc->hwmode, &crtc->state->adjusted_mode); tilcdc_crtc->hvtotal_us = tilcdc_mode_hvtotal(&crtc->hwmode);