From 8bd7b0b2a932e19e9cbb2cdae5953e676f1a73a3 Mon Sep 17 00:00:00 2001 From: Ioana Ciornei Date: Thu, 16 Oct 2025 16:58:07 +0300 Subject: [PATCH] dpaa2-eth: fix the pointer passed to PTR_ALIGN on Tx path [ Upstream commit 902e81e679d86846a2404630d349709ad9372d0d ] The blamed commit increased the needed headroom to account for alignment. This means that the size required to always align a Tx buffer was added inside the dpaa2_eth_needed_headroom() function. By doing that, a manual adjustment of the pointer passed to PTR_ALIGN() was no longer correct since the 'buffer_start' variable was already pointing to the start of the skb's memory. The behavior of the dpaa2-eth driver without this patch was to drop frames on Tx even when the headroom was matching the 128 bytes necessary. Fix this by removing the manual adjust of 'buffer_start' from the PTR_MODE call. Closes: https://lore.kernel.org/netdev/70f0dcd9-1906-4d13-82df-7bbbbe7194c6@app.fastmail.com/T/#u Fixes: f422abe3f23d ("dpaa2-eth: increase the needed headroom to account for alignment") Signed-off-by: Ioana Ciornei Tested-by: Mathew McBride Reviewed-by: Simon Horman Link: https://patch.msgid.link/20251016135807.360978-1-ioana.ciornei@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c index 0f4efd5053320..a5f3d19f1466c 100644 --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c @@ -1077,8 +1077,7 @@ static int dpaa2_eth_build_single_fd(struct dpaa2_eth_priv *priv, dma_addr_t addr; buffer_start = skb->data - dpaa2_eth_needed_headroom(skb); - aligned_start = PTR_ALIGN(buffer_start - DPAA2_ETH_TX_BUF_ALIGN, - DPAA2_ETH_TX_BUF_ALIGN); + aligned_start = PTR_ALIGN(buffer_start, DPAA2_ETH_TX_BUF_ALIGN); if (aligned_start >= skb->head) buffer_start = aligned_start; else -- 2.47.3