[PATCH net-next 10/15] net/mlx5e: Alloc rq drop page based on calculated page_shift

[Tariq Toukan]

From: Dragos Tatulea <dtatulea@xxxxxxxxxx>

An upcoming patch will allow setting the page order for RX
pages to be greater than 0. Make sure that the drop page will
also be allocated with the right size when that happens.

Take extra care when calculating the drop page size to
account for page_shift < PAGE_SHIFT which can happen for xsk.

Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 27 ++++++++++++-------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 6344dbb6335e..2d3d89707246 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -636,14 +636,18 @@ static void mlx5e_rq_timeout_work(struct work_struct *timeout_work)
 
 static int mlx5e_alloc_mpwqe_rq_drop_page(struct mlx5e_rq *rq)
 {
-	rq->wqe_overflow.page = alloc_page(GFP_KERNEL);
+	/* xsk can have page_shift < PAGE_SHIFT */
+	u16 page_order = max_t(s16, rq->mpwqe.page_shift - PAGE_SHIFT, 0);
+	u32 page_size = BIT(PAGE_SHIFT + page_order);
+
+	rq->wqe_overflow.page = alloc_pages(GFP_KERNEL, page_order);
 	if (!rq->wqe_overflow.page)
 		return -ENOMEM;
 
 	rq->wqe_overflow.addr = dma_map_page(rq->pdev, rq->wqe_overflow.page, 0,
-					     PAGE_SIZE, rq->buff.map_dir);
+					     page_size, rq->buff.map_dir);
 	if (dma_mapping_error(rq->pdev, rq->wqe_overflow.addr)) {
-		__free_page(rq->wqe_overflow.page);
+		__free_pages(rq->wqe_overflow.page, page_order);
 		return -ENOMEM;
 	}
 	return 0;
@@ -651,9 +655,12 @@ static int mlx5e_alloc_mpwqe_rq_drop_page(struct mlx5e_rq *rq)
 
 static void mlx5e_free_mpwqe_rq_drop_page(struct mlx5e_rq *rq)
 {
-	 dma_unmap_page(rq->pdev, rq->wqe_overflow.addr, PAGE_SIZE,
-			rq->buff.map_dir);
-	 __free_page(rq->wqe_overflow.page);
+	u16 page_order = max_t(s16, rq->mpwqe.page_shift - PAGE_SHIFT, 0);
+	u32 page_size = BIT(PAGE_SHIFT + page_order);
+
+	dma_unmap_page(rq->pdev, rq->wqe_overflow.addr, page_size,
+		       rq->buff.map_dir);
+	 __free_pages(rq->wqe_overflow.page, page_order);
 }
 
 static int mlx5e_init_rxq_rq(struct mlx5e_channel *c, struct mlx5e_params *params,
@@ -884,15 +891,15 @@ static int mlx5e_alloc_rq(struct mlx5e_params *params,
 		if (err)
 			goto err_rq_xdp_prog;
 
-		err = mlx5e_alloc_mpwqe_rq_drop_page(rq);
-		if (err)
-			goto err_rq_wq_destroy;
-
 		rq->mpwqe.wq.db = &rq->mpwqe.wq.db[MLX5_RCV_DBR];
 
 		wq_sz = mlx5_wq_ll_get_size(&rq->mpwqe.wq);
 
 		rq->mpwqe.page_shift = mlx5e_mpwrq_page_shift(mdev, rqo);
+		err = mlx5e_alloc_mpwqe_rq_drop_page(rq);
+		if (err)
+			goto err_rq_wq_destroy;
+
 		rq->mpwqe.umr_mode = mlx5e_mpwrq_umr_mode(mdev, rqo);
 		rq->mpwqe.pages_per_wqe =
 			mlx5e_mpwrq_pages_per_wqe(mdev, rq->mpwqe.page_shift,
-- 
2.44.0