netdev - [PATCH bpf 4/6] i40e: use truesize as XDP RxQ info frag

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Message-ID: <20260203105417.2302672-5-larysa.zaremba@intel.com>
Date: Tue,  3 Feb 2026 11:53:32 +0100
From: Larysa Zaremba <larysa.zaremba@...el.com>
To: bpf@...r.kernel.org
Cc: Claudiu Manoil <claudiu.manoil@....com>,
	Vladimir Oltean <vladimir.oltean@....com>,
	Wei Fang <wei.fang@....com>,
	Clark Wang <xiaoning.wang@....com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Tony Nguyen <anthony.l.nguyen@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	John Fastabend <john.fastabend@...il.com>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	KP Singh <kpsingh@...nel.org>,
	Hao Luo <haoluo@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Simon Horman <horms@...nel.org>,
	Shuah Khan <shuah@...nel.org>,
	Alexander Lobakin <aleksander.lobakin@...el.com>,
	Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
	"Bastien Curutchet (eBPF Foundation)" <bastien.curutchet@...tlin.com>,
	Larysa Zaremba <larysa.zaremba@...el.com>,
	Tushar Vyavahare <tushar.vyavahare@...el.com>,
	Jason Xing <kernelxing@...cent.com>,
	Ricardo B. Marlière <rbm@...e.com>,
	Eelco Chaudron <echaudro@...hat.com>,
	Lorenzo Bianconi <lorenzo@...nel.org>,
	Toke Hoiland-Jorgensen <toke@...hat.com>,
	imx@...ts.linux.dev,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	intel-wired-lan@...ts.osuosl.org,
	linux-kselftest@...r.kernel.org,
	Aleksandr Loktionov <aleksandr.loktionov@...el.com>
Subject: [PATCH bpf 4/6] i40e: use truesize as XDP RxQ info frag_size

The only user of frag_size field in XDP RxQ info is
bpf_xdp_frags_increase_tail(). It clearly expects truesize instead of DMA
write size. Different assumptions in i40e driver configuration lead to
negative tailroom.

Set frag_size to the same value as frame_sz.

Fixes: a045d2f2d03d ("i40e: set xdp_rxq_info::frag_size")
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@...el.com>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 0b1cc0481027..72a33aa3e1f3 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -3561,6 +3561,7 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 	struct i40e_vsi *vsi = ring->vsi;
 	u32 chain_len = vsi->back->hw.func_caps.rx_buf_chain_len;
 	u16 pf_q = vsi->base_queue + ring->queue_index;
+	u32 truesize = i40e_rx_pg_size(ring) / 2;
 	struct i40e_hw *hw = &vsi->back->hw;
 	struct i40e_hmc_obj_rxq rx_ctx;
 	int err = 0;
@@ -3581,7 +3582,7 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 		err = __xdp_rxq_info_reg(&ring->xdp_rxq, ring->netdev,
 					 ring->queue_index,
 					 ring->q_vector->napi.napi_id,
-					 ring->rx_buf_len);
+					 truesize);
 		if (err)
 			return err;
 	}
@@ -3614,7 +3615,7 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 	}
 
 skip:
-	xdp_init_buff(&ring->xdp, i40e_rx_pg_size(ring) / 2, &ring->xdp_rxq);
+	xdp_init_buff(&ring->xdp, truesize, &ring->xdp_rxq);
 
 	rx_ctx.dbuff = DIV_ROUND_UP(ring->rx_buf_len,
 				    BIT_ULL(I40E_RXQ_CTX_DBUFF_SHIFT));
-- 
2.52.0