There is no need to look at the port's VCPI allocation before calling drm_dp_mst_deallocate_vcpi(), as we already have msto->disabled to let us avoid cleaning up an msto more then once. The DP MST core will never call drm_dp_mst_deallocate_vcpi() on it's own, which is presumably what these checks are meant to protect against.
More importantly though, we're about to stop clearing mstc->port in the next commit, which means if we could potentially hit a use-after-free error if we tried to check mstc->port->vcpi here. So to make life easier for anyone who bisects this code in the future, use msto->disabled instead to check whether or not we need to deallocate VCPI instead.
Signed-off-by: Lyude Paul lyude@redhat.com Cc: Daniel Vetter daniel@ffwll.ch Cc: David Airlie airlied@redhat.com Cc: Jerry Zuo Jerry.Zuo@amd.com Cc: Harry Wentland harry.wentland@amd.com Cc: Juston Li juston.li@intel.com --- drivers/gpu/drm/nouveau/dispnv50/disp.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index 641252208e67..0f7d72518604 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -704,14 +704,17 @@ nv50_msto_cleanup(struct nv50_msto *msto) struct nv50_mstc *mstc = msto->mstc; struct nv50_mstm *mstm = mstc->mstm;
+ if (!msto->disabled) + return; + NV_ATOMIC(drm, "%s: msto cleanup\n", msto->encoder.name); - if (mstc->port && mstc->port->vcpi.vcpi > 0 && !nv50_msto_payload(msto)) + + if (mstc->port) drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port); - if (msto->disabled) { - msto->mstc = NULL; - msto->head = NULL; - msto->disabled = false; - } + + msto->mstc = NULL; + msto->head = NULL; + msto->disabled = false; }
static void