RDMA/mlx5: Remove mlx5_ib_mr->order

The is only ever set to non-zero if the MR is from the cache, and if it is
cached then the order is in cached_ent->order.

Make it clearer that use_umr_mtt_update() only returns true for cached MRs
and remove the redundant data.

Link: https://lore.kernel.org/r/20201026131936.1335664-2-leon@kernel.orgSigned-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -601,7 +601,6 @@ struct mlx5_ib_mr {
 	struct ib_umem	       *umem;
 	struct mlx5_shared_mr_info	*smr_info;
 	struct list_head	list;
-	unsigned int		order;
 	struct mlx5_cache_ent  *cache_ent;
 	int			npages;
 	struct mlx5_ib_dev     *dev;

drivers/infiniband/hw/mlx5/mr.c

@@ -126,7 +126,9 @@ static int destroy_mkey(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)
 static inline bool mlx5_ib_pas_fits_in_mr(struct mlx5_ib_mr *mr, u64 start,
 					  u64 length)
 {
-	return ((u64)1 << mr->order) * MLX5_ADAPTER_PAGE_SIZE >=
+	if (!mr->cache_ent)
+		return false;
+	return ((u64)1 << mr->cache_ent->order) * MLX5_ADAPTER_PAGE_SIZE >=
 		length + (start & (MLX5_ADAPTER_PAGE_SIZE - 1));
 }
 
@@ -172,7 +174,6 @@ static struct mlx5_ib_mr *alloc_cache_mr(struct mlx5_cache_ent *ent, void *mkc)
 	mr = kzalloc(sizeof(*mr), GFP_KERNEL);
 	if (!mr)
 		return NULL;
-	mr->order = ent->order;
 	mr->cache_ent = ent;
 	mr->dev = ent->dev;