On 2021-07-20 3:11 p.m., Christian König wrote: > Daniel pointed me towards this function and there are multiple obvious problems > in the implementation. > > First of all the retry loop is not working as intended. In general the retry > makes only sense if you grab the reference first and then check the sequence > values. > > Then we should always also wait for the exclusive fence. > > It's also good practice to keep the reference around when installing callbacks > to fences you don't own. > > And last the whole implementation was unnecessary complex and rather hard to > understand which could lead to probably unexpected behavior of the IOCTL. > > Fix all this by reworking the implementation from scratch. Dropping the > whole RCU approach and taking the lock instead. > > Only mildly tested and needs a thoughtful review of the code. > > v2: fix the reference counting as well > v3: keep the excl fence handling as is for stable > v4: back to testing all fences, drop RCU > v5: handle in and out separately > v6: add missing clear of events > v7: change coding style as suggested by Michel, drop unused variables > > Signed-off-by: Christian König <christian.koenig@xxxxxxx> > CC: stable@xxxxxxxxxxxxxxx Working fine with https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1880 Tested-by: Michel Dänzer <mdaenzer@xxxxxxxxxx> -- Earthling Michel Dänzer | https://redhat.com Libre software enthusiast | Mesa and X developer
