IB/mlx5: Fix implicit MR GC

When implicit MR's leaf MKey becomes unused, i.e. when it's
last page being released my MMU invalidation it is marked as "dying"
and scheduled for release by garbage collector.
Currentle consequent page fault may remove "dying" flag.
Treat leaf MKey as non-existent once it was scheduled to removal
by GC.

Fixes: 81713d3788d2 ('IB/mlx5: Add implicit MR support')
Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 3bfa3a9c3be03f5996ed8053bba48ebf5e91646e..b506321f5cb7766f375f17bba7ad6b1819230f7f 100644 (file)
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -57,7 +57,7 @@ static int check_parent(struct ib_umem_odp *odp,
 {
        struct mlx5_ib_mr *mr = odp->private;
 
-       return mr && mr->parent == parent;
+       return mr && mr->parent == parent && !odp->dying;
 }
 
 static struct ib_umem_odp *odp_next(struct ib_umem_odp *odp)
@@ -158,13 +158,6 @@ static void mr_leaf_free_action(struct work_struct *work)
        mr->parent = NULL;
        synchronize_srcu(&mr->dev->mr_srcu);
 
-       if (!READ_ONCE(odp->dying)) {
-               mr->parent = imr;
-               if (atomic_dec_and_test(&imr->num_leaf_free))
-                       wake_up(&imr->q_leaf_free);
-               return;
-       }
-
        ib_umem_release(odp->umem);
        if (imr->live)
                mlx5_ib_update_xlt(imr, idx, 1, 0,
@@ -436,8 +429,6 @@ static struct ib_umem_odp *implicit_mr_get_data(struct mlx5_ib_mr *mr,
                nentries++;
        }
 
-       odp->dying = 0;
-
        /* Return first odp if region not covered by single one */
        if (likely(!result))
                result = odp;