net: stmmac: Set dma_sync_size to zero for discarded frames

If a frame is going to be discarded by driver, this frame is never touched
by driver and the cache lines never become dirty obviously,
page_pool_recycle_direct() wastes CPU cycles on unnecessary calling of
page_pool_dma_sync_for_device() to sync entire frame.
page_pool_put_page() with sync_size setting to 0 is the proper method.

Signed-off-by: Furong Xu <0x1207@gmail.com>
Link: https://patch.msgid.link/20250103093733.3872939-1-0x1207@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2f518ec..70c8f60 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5467,7 +5467,7 @@ read_again:
                if (priv->extend_desc)
                        stmmac_rx_extended_status(priv, &priv->xstats, rx_q->dma_erx + entry);
                if (unlikely(status == discard_frame)) {
-                       page_pool_recycle_direct(rx_q->page_pool, buf->page);
+                       page_pool_put_page(rx_q->page_pool, buf->page, 0, true);
                        buf->page = NULL;
                        error = 1;
                        if (!priv->hwts_rx_en)