MANA passes rxq->alloc_size to napi_build_skb() for all RX buffers. It is correct for fragment-backed RX buffers, where alloc_size matches the actual backing allocation used for each packet buffer. However, in the non-fragment RX path mana allocates a full page, or a higher-order page, per RX buffer. In that case alloc_size only reflects the usable packet area and not the actual backing memory. This causes napi_build_skb() to underestimate the skb backing allocation in the single-buffer RX path, so skb->truesize is derived from a value smaller than the real RX buffer allocation. Fix this by updating alloc_size in the non-fragment RX path to the actual backing allocation size before it is passed to napi_build_skb(). Fixes: 730ff06d3f5c ("net: mana: Use page pool fragments for RX buffers instead of full pages to improve memory efficiency.") Signed-off-by: Dipayaan Roy --- drivers/net/ethernet/microsoft/mana/mana_en.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c index ea71de39f996..884f8e548174 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -766,6 +766,13 @@ static void mana_get_rxbuf_cfg(struct mana_port_context *apc, } *frag_count = 1; + + /* In the single-buffer path, napi_build_skb() must see the + * actual backing allocation size so skb->truesize reflects + * the full page (or higher-order page), not just the usable + * packet area. + */ + *alloc_size = PAGE_SIZE << get_order(*alloc_size); return; } -- 2.43.0