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 --- 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 c96d1d6ba8fe..18d86badd6ea 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 -- 2.25.1