From 872ad758f9b7fb4eb42aebaf64e50c5b29b7ffe5 Mon Sep 17 00:00:00 2001 From: Horatiu Vultur Date: Sun, 30 Oct 2022 22:36:36 +0100 Subject: net: lan966x: Fix FDMA when MTU is changed When MTU is changed, FDMA is required to calculate what is the maximum size of the frame that it can received. So it can calculate what is the page order needed to allocate for the received frames. The first problem was that, when the max MTU was calculated it was reading the value from dev and not from HW, so in this way it was missing L2 header + the FCS. The other problem was that once the skb is created using __build_skb_around, it would reserve some space for skb_shared_info. So if we received a frame which size is at the limit of the page order then the creating will failed because it would not have space to put all the data. Fixes: 2ea1cbac267e ("net: lan966x: Update FDMA to change MTU.") Signed-off-by: Horatiu Vultur Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c | 8 ++++++-- drivers/net/ethernet/microchip/lan966x/lan966x_main.c | 2 +- 2 files changed, 7 insertions(+), 3 deletions(-) (limited to 'drivers/net/ethernet') diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c index a42035cec611..c235edd2b182 100644 --- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c @@ -668,12 +668,14 @@ static int lan966x_fdma_get_max_mtu(struct lan966x *lan966x) int i; for (i = 0; i < lan966x->num_phys_ports; ++i) { + struct lan966x_port *port; int mtu; - if (!lan966x->ports[i]) + port = lan966x->ports[i]; + if (!port) continue; - mtu = lan966x->ports[i]->dev->mtu; + mtu = lan_rd(lan966x, DEV_MAC_MAXLEN_CFG(port->chip_port)); if (mtu > max_mtu) max_mtu = mtu; } @@ -733,6 +735,8 @@ int lan966x_fdma_change_mtu(struct lan966x *lan966x) max_mtu = lan966x_fdma_get_max_mtu(lan966x); max_mtu += IFH_LEN * sizeof(u32); + max_mtu += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + max_mtu += VLAN_HLEN * 2; if (round_up(max_mtu, PAGE_SIZE) / PAGE_SIZE - 1 == lan966x->rx.page_order) diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c index b3070c3fcad0..20ee5b28f70a 100644 --- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c @@ -395,7 +395,7 @@ static int lan966x_port_change_mtu(struct net_device *dev, int new_mtu) err = lan966x_fdma_change_mtu(lan966x); if (err) { - lan_wr(DEV_MAC_MAXLEN_CFG_MAX_LEN_SET(old_mtu), + lan_wr(DEV_MAC_MAXLEN_CFG_MAX_LEN_SET(LAN966X_HW_MTU(old_mtu)), lan966x, DEV_MAC_MAXLEN_CFG(port->chip_port)); dev->mtu = old_mtu; } -- cgit v1.2.3