mlx5: more strict use of page_pool API

The mlx5 driver is using page_pool, but not for DMA-mapping (currently), and
is a little too relaxed about returning or releasing page resources, as it
is not strictly necessary, when not using DMA-mappings.

As this patchset is working towards tracking page_pool resources, to know
about in-flight frames on shutdown. Then fix places where mlx5 leak
page_pool resource.

In case of dma_mapping_error, then recycle into page_pool.

In mlx5e_free_rq() moved the page_pool_destroy() call to after the
mlx5e_page_release() calls, as it is more correct.

In mlx5e_page_release() when no recycle was requested, then release page
from the page_pool, via page_pool_release_page().
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -625,10 +625,6 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
 	if (rq->xdp_prog)
 		bpf_prog_put(rq->xdp_prog);
 
-	xdp_rxq_info_unreg(&rq->xdp_rxq);
-	if (rq->page_pool)
-		page_pool_destroy(rq->page_pool);
-
 	switch (rq->wq_type) {
 	case MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ:
 		kvfree(rq->mpwqe.info);
@@ -645,6 +641,11 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
 
 		mlx5e_page_release(rq, dma_info, false);
 	}
+
+	xdp_rxq_info_unreg(&rq->xdp_rxq);
+	if (rq->page_pool)
+		page_pool_destroy(rq->page_pool);
+
 	mlx5_wq_destroy(&rq->wq_ctrl);
 }
 

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -248,7 +248,7 @@ static inline int mlx5e_page_alloc_mapped(struct mlx5e_rq *rq,
 	dma_info->addr = dma_map_page(rq->pdev, dma_info->page, 0,
 				      PAGE_SIZE, rq->buff.map_dir);
 	if (unlikely(dma_mapping_error(rq->pdev, dma_info->addr))) {
-		put_page(dma_info->page);
+		page_pool_recycle_direct(rq->page_pool, dma_info->page);
 		dma_info->page = NULL;
 		return -ENOMEM;
 	}
@@ -272,6 +272,7 @@ void mlx5e_page_release(struct mlx5e_rq *rq, struct mlx5e_dma_info *dma_info,
 		page_pool_recycle_direct(rq->page_pool, dma_info->page);
 	} else {
 		mlx5e_page_dma_unmap(rq, dma_info);
+		page_pool_release_page(rq->page_pool, dma_info->page);
 		put_page(dma_info->page);
 	}
 }