From 1eb2cded45b35816085c1f962933c187d970f9dc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 6 May 2024 10:28:12 +0000 Subject: net: annotate writes on dev->mtu from ndo_change_mtu() Simon reported that ndo_change_mtu() methods were never updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted in commit 501a90c94510 ("inet: protect against too small mtu values.") We read dev->mtu without holding RTNL in many places, with READ_ONCE() annotations. It is time to take care of ndo_change_mtu() methods to use corresponding WRITE_ONCE() Signed-off-by: Eric Dumazet Reported-by: Simon Horman Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/ Reviewed-by: Jacob Keller Reviewed-by: Sabrina Dubroca Reviewed-by: Simon Horman Acked-by: Shannon Nelson Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/ibm/emac/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/ethernet/ibm/emac/core.c') diff --git a/drivers/net/ethernet/ibm/emac/core.c b/drivers/net/ethernet/ibm/emac/core.c index e6e47b1842ea..a19d098f2e2b 100644 --- a/drivers/net/ethernet/ibm/emac/core.c +++ b/drivers/net/ethernet/ibm/emac/core.c @@ -1098,7 +1098,7 @@ static int emac_resize_rx_ring(struct emac_instance *dev, int new_mtu) /* This is to prevent starting RX channel in emac_rx_enable() */ set_bit(MAL_COMMAC_RX_STOPPED, &dev->commac.flags); - dev->ndev->mtu = new_mtu; + WRITE_ONCE(dev->ndev->mtu, new_mtu); emac_full_tx_reset(dev); } @@ -1130,7 +1130,7 @@ static int emac_change_mtu(struct net_device *ndev, int new_mtu) } if (!ret) { - ndev->mtu = new_mtu; + WRITE_ONCE(ndev->mtu, new_mtu); dev->rx_skb_size = emac_rx_skb_size(new_mtu); dev->rx_sync_size = emac_rx_sync_size(new_mtu); } -- cgit v1.2.3