RDMA: Check umem pointer validity prior to release

Update ib_umem_release() to behave similarly to kfree() and allow
submitting NULL pointer as safe input to this function.

Fixes: a52c8e2469c3 ("RDMA: Clean destroy CQ in drivers do not return errors")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 4d033796dcfc..994abcebb057 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1507,10 +1507,9 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
         return 0;
 
 err:
-        if (mr->umem) {
-                ib_umem_release(mr->umem);
-                mr->umem = NULL;
-        }
+        ib_umem_release(mr->umem);
+        mr->umem = NULL;
+
         clean_mr(dev, mr);
         return err;
 }
@@ -1630,10 +1629,10 @@ static void dereg_mr(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)
          * remove the DMA mapping.
          */
         mlx5_mr_cache_free(dev, mr);
-        if (umem) {
-                ib_umem_release(umem);
+        ib_umem_release(umem);
+        if (umem)
                 atomic_sub(npages, &dev->mdev->priv.reg_pages);
-        }
+
         if (!mr->allocated_from_cache)
                 kfree(mr);
 }