git.openwrt.org Git - openwrt/staging/neocturne.git/blob

   1 From 1eb2cded45b35816085c1f962933c187d970f9dc Mon Sep 17 00:00:00 2001
   2 From: Eric Dumazet <edumazet@google.com>
   3 Date: Mon, 6 May 2024 10:28:12 +0000
   4 Subject: [PATCH] net: annotate writes on dev->mtu from ndo_change_mtu()
   5
   6 Simon reported that ndo_change_mtu() methods were never
   7 updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted
   8 in commit 501a90c94510 ("inet: protect against too small
   9 mtu values.")
  10
  11 We read dev->mtu without holding RTNL in many places,
  12 with READ_ONCE() annotations.
  13
  14 It is time to take care of ndo_change_mtu() methods
  15 to use corresponding WRITE_ONCE()
  16
  17 Signed-off-by: Eric Dumazet <edumazet@google.com>
  18 Reported-by: Simon Horman <horms@kernel.org>
  19 Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/
  20 Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
  21 Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
  22 Reviewed-by: Simon Horman <horms@kernel.org>
  23 Acked-by: Shannon Nelson <shannon.nelson@amd.com>
  24 Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com
  25 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  26 ---
  27  drivers/net/ethernet/realtek/8139cp.c     | 4 ++--
  28  drivers/net/ethernet/realtek/r8169_main.c | 2 +-
  29  2 files changed, 3 insertions(+), 3 deletions(-)
  30
  31 --- a/drivers/net/ethernet/realtek/8139cp.c
  32 +++ b/drivers/net/ethernet/realtek/8139cp.c
  33 @@ -1277,14 +1277,14 @@ static int cp_change_mtu(struct net_devi
  34
  35         /* if network interface not up, no need for complexity */
  36         if (!netif_running(dev)) {
  37 -               dev->mtu = new_mtu;
  38 +               WRITE_ONCE(dev->mtu, new_mtu);
  39                 cp_set_rxbufsize(cp);   /* set new rx buf size */
  40                 return 0;
  41         }
  42
  43         /* network IS up, close it, reset MTU, and come up again. */
  44         cp_close(dev);
  45 -       dev->mtu = new_mtu;
  46 +       WRITE_ONCE(dev->mtu, new_mtu);
  47         cp_set_rxbufsize(cp);
  48         return cp_open(dev);
  49  }
  50 --- a/drivers/net/ethernet/realtek/r8169_main.c
  51 +++ b/drivers/net/ethernet/realtek/r8169_main.c
  52 @@ -3925,7 +3925,7 @@ static int rtl8169_change_mtu(struct net
  53  {
  54         struct rtl8169_private *tp = netdev_priv(dev);
  55
  56 -       dev->mtu = new_mtu;
  57 +       WRITE_ONCE(dev->mtu, new_mtu);
  58         netdev_update_features(dev);
  59         rtl_jumbo_config(tp);
  60         rtl_set_eee_txidle_timer(tp);