On Sun, Sep 06, 2015 at 06:53:00PM +1000, Dave Airlie wrote: > There is a race where the reply could get processed by another > work queue before we've updated the state. > > Update the state before sending the msg to close it. > > v2: reset value if return indicates we haven't send the msg. > > Pointed out by Adam J Richter on > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91481 > Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx> Ok we see to have two callers of drm_dp_send_link_address: - drm_dp_add_port, but the only caller of that in turn is again drm_dp_send_link_address. This is just self-recursion. - drm_dp_check_and_send_link_address, which in turn is called only by itself and by drm_dp_mst_link_probe_work. drm_dp_mst_link_probe_work is only called from the mgr->work function, and a single work item is never run concurrently. I don't see any race here at all. A good cleanup though would be what Adam's original patch has done and move the link_address_sent = true into drm_dp_send_link_address. Cheers, Daniel > --- > drivers/gpu/drm/drm_dp_mst_topology.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c > index 294d904..831096b9 100644 > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > @@ -1101,8 +1101,10 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb, > > ret = drm_dp_port_setup_pdt(port); > if (ret == true) { > - drm_dp_send_link_address(mstb->mgr, port->mstb); > port->mstb->link_address_sent = true; > + ret = drm_dp_send_link_address(mstb->mgr, port->mstb); > + if (ret < 0) > + port->mstb->link_address_sent = false; > } > } > > @@ -1198,8 +1200,11 @@ static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m > struct drm_dp_mst_port *port; > struct drm_dp_mst_branch *mstb_child; > if (!mstb->link_address_sent) { > - drm_dp_send_link_address(mgr, mstb); > + int ret; > mstb->link_address_sent = true; > + ret = drm_dp_send_link_address(mgr, mstb); > + if (ret < 0) > + mstb->link_address_sent = false; > } > list_for_each_entry(port, &mstb->ports, next) { > if (port->input) > @@ -1493,11 +1498,12 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr, > } > (*mgr->cbs->hotplug)(mgr); > } > + ret = 0; > } else > DRM_DEBUG_KMS("link address failed %d\n", ret); > > kfree(txmsg); > - return 0; > + return ret; > } > > static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr, > -- > 2.4.3 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
