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Commit 5e292e76 authored by Lyude Paul's avatar Lyude Paul
Browse files

drm/nouveau: Remove unnecessary VCPI checks in nv50_msto_cleanup() 



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: default avatarLyude Paul <lyude@redhat.com>
Reviewed-by: default avatarBen Skeggs <bskeggs@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>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-14-lyude@redhat.com
parent 01324093

drivers/gpu/drm/nouveau/dispnv50/disp.c

+9 −6
Original line number Diff line number Diff line
@@ -696,15 +696,18 @@ 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;

}

}



static void

nv50_msto_prepare(struct nv50_msto *msto)