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

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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>
Reviewed-by: Ben 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
This commit is contained in:
Lyude Paul 2019-01-10 19:53:36 -05:00
parent 013240935d
commit 5e292e7646
1 changed files with 9 additions and 6 deletions
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15
drivers/gpu/drm/nouveau/dispnv50/disp.c
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@ -696,14 +696,17 @@ 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