From c8a36f1945b2b1b3f9823b66fc2181dc069cf803 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 19 Aug 2020 22:28:41 -0700 Subject: bpf: xdp: Fix XDP mode when no mode flags specified 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device") inadvertently changed which XDP mode is assumed when no mode flags are specified explicitly. Previously, driver mode was preferred, if driver supported it. If not, generic SKB mode was chosen. That commit changed default to SKB mode always. This patch fixes the issue and restores the original logic. Fixes: 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device") Reported-by: Lorenzo Bianconi Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Tested-by: Lorenzo Bianconi Link: https://lore.kernel.org/bpf/20200820052841.1559757-1-andriin@fb.com --- net/core/dev.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'net') diff --git a/net/core/dev.c b/net/core/dev.c index b5d1129d8310..d42c9ea0c3c0 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8742,13 +8742,15 @@ struct bpf_xdp_link { int flags; }; -static enum bpf_xdp_mode dev_xdp_mode(u32 flags) +static enum bpf_xdp_mode dev_xdp_mode(struct net_device *dev, u32 flags) { if (flags & XDP_FLAGS_HW_MODE) return XDP_MODE_HW; if (flags & XDP_FLAGS_DRV_MODE) return XDP_MODE_DRV; - return XDP_MODE_SKB; + if (flags & XDP_FLAGS_SKB_MODE) + return XDP_MODE_SKB; + return dev->netdev_ops->ndo_bpf ? XDP_MODE_DRV : XDP_MODE_SKB; } static bpf_op_t dev_xdp_bpf_op(struct net_device *dev, enum bpf_xdp_mode mode) @@ -8896,7 +8898,7 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack return -EINVAL; } - mode = dev_xdp_mode(flags); + mode = dev_xdp_mode(dev, flags); /* can't replace attached link */ if (dev_xdp_link(dev, mode)) { NL_SET_ERR_MSG(extack, "Can't replace active BPF XDP link"); @@ -8984,7 +8986,7 @@ static int dev_xdp_detach_link(struct net_device *dev, ASSERT_RTNL(); - mode = dev_xdp_mode(link->flags); + mode = dev_xdp_mode(dev, link->flags); if (dev_xdp_link(dev, mode) != link) return -EINVAL; @@ -9080,7 +9082,7 @@ static int bpf_xdp_link_update(struct bpf_link *link, struct bpf_prog *new_prog, goto out_unlock; } - mode = dev_xdp_mode(xdp_link->flags); + mode = dev_xdp_mode(xdp_link->dev, xdp_link->flags); bpf_op = dev_xdp_bpf_op(xdp_link->dev, mode); err = dev_xdp_install(xdp_link->dev, mode, bpf_op, NULL, xdp_link->flags, new_prog); @@ -9164,7 +9166,7 @@ out_put_dev: int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, int fd, int expected_fd, u32 flags) { - enum bpf_xdp_mode mode = dev_xdp_mode(flags); + enum bpf_xdp_mode mode = dev_xdp_mode(dev, flags); struct bpf_prog *new_prog = NULL, *old_prog = NULL; int err; -- cgit v1.2.3