| Message ID | 20220218100403.7028-6-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Review of mode copies | expand |
Applied. Thanks! Alex On Fri, Feb 18, 2022 at 5:04 AM Ville Syrjala <ville.syrjala@linux.intel.com> 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: Alex Deucher <alexander.deucher@amd.com> > Cc: amd-gfx@lists.freedesktop.org > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/radeon/radeon_connectors.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c > index a7925a8290b2..0cb1345c6ba4 100644 > --- a/drivers/gpu/drm/radeon/radeon_connectors.c > +++ b/drivers/gpu/drm/radeon/radeon_connectors.c > @@ -777,7 +777,7 @@ static void radeon_fixup_lvds_native_mode(struct drm_encoder *encoder, > if (mode->type & DRM_MODE_TYPE_PREFERRED) { > if (mode->hdisplay != native_mode->hdisplay || > mode->vdisplay != native_mode->vdisplay) > - memcpy(native_mode, mode, sizeof(*mode)); > + drm_mode_copy(native_mode, mode); > } > } > > @@ -786,7 +786,7 @@ static void radeon_fixup_lvds_native_mode(struct drm_encoder *encoder, > list_for_each_entry_safe(mode, t, &connector->probed_modes, head) { > if (mode->hdisplay == native_mode->hdisplay && > mode->vdisplay == native_mode->vdisplay) { > - *native_mode = *mode; > + drm_mode_copy(native_mode, mode); > drm_mode_set_crtcinfo(native_mode, CRTC_INTERLACE_HALVE_V); > DRM_DEBUG_KMS("Determined LVDS native mode details from EDID\n"); > break; > -- > 2.34.1 >
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c index a7925a8290b2..0cb1345c6ba4 100644 --- a/drivers/gpu/drm/radeon/radeon_connectors.c +++ b/drivers/gpu/drm/radeon/radeon_connectors.c @@ -777,7 +777,7 @@ static void radeon_fixup_lvds_native_mode(struct drm_encoder *encoder, if (mode->type & DRM_MODE_TYPE_PREFERRED) { if (mode->hdisplay != native_mode->hdisplay || mode->vdisplay != native_mode->vdisplay) - memcpy(native_mode, mode, sizeof(*mode)); + drm_mode_copy(native_mode, mode); } } @@ -786,7 +786,7 @@ static void radeon_fixup_lvds_native_mode(struct drm_encoder *encoder, list_for_each_entry_safe(mode, t, &connector->probed_modes, head) { if (mode->hdisplay == native_mode->hdisplay && mode->vdisplay == native_mode->vdisplay) { - *native_mode = *mode; + drm_mode_copy(native_mode, mode); drm_mode_set_crtcinfo(native_mode, CRTC_INTERLACE_HALVE_V); DRM_DEBUG_KMS("Determined LVDS native mode details from EDID\n"); break;