8a48ac7f6c
Fix a race in rxe_mcast.c that occurs when two QPs try at the same time to attach a multicast address. Both QPs lookup the mgid address in a pool of multicast groups and if they do not find it create a new group elem. Fix this by locking the lookup/alloc/add key sequence and using the unlocked APIs added in this patch set. Link: https://lore.kernel.org/r/20201216231550.27224-8-rpearson@hpe.com Signed-off-by: Bob Pearson <rpearson@hpe.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>