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authorJens Axboe <axboe@kernel.dk>2022-07-25 03:41:03 +0300
committerJens Axboe <axboe@kernel.dk>2022-07-25 03:41:03 +0300
commit4effe18fc0da27ae5d51a702841e87fa13b8a32d (patch)
tree468f353a3713c93b27e7b2c262efd747e66ff199 /net/core/dev.c
parent32e09298c8b3ff29177c825ab711a4a692d4caad (diff)
parentf6b543fd03d347e8bf245cee4f2d54eb6ffd8fcb (diff)
downloadlinux-4effe18fc0da27ae5d51a702841e87fa13b8a32d.tar.xz
Merge branch 'for-5.20/io_uring' into for-5.20/io_uring-zerocopy-send
* for-5.20/io_uring: (716 commits) io_uring: ensure REQ_F_ISREG is set async offload net: fix compat pointer in get_compat_msghdr() io_uring: Don't require reinitable percpu_ref io_uring: fix types in io_recvmsg_multishot_overflow io_uring: Use atomic_long_try_cmpxchg in __io_account_mem io_uring: support multishot in recvmsg net: copy from user before calling __get_compat_msghdr net: copy from user before calling __copy_msghdr io_uring: support 0 length iov in buffer select in compat io_uring: fix multishot ending when not polled io_uring: add netmsg cache io_uring: impose max limit on apoll cache io_uring: add abstraction around apoll cache io_uring: move apoll cache to poll.c io_uring: consolidate hash_locked io-wq handling io_uring: clear REQ_F_HASH_LOCKED on hash removal io_uring: don't race double poll setting REQ_F_ASYNC_DATA io_uring: don't miss setting REQ_F_DOUBLE_POLL io_uring: disable multishot recvmsg io_uring: only trace one of complete or overflow ... Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r--net/core/dev.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 8e6f22961206..30a1603a7225 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4863,7 +4863,10 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb,
}
/* When doing generic XDP we have to bypass the qdisc layer and the
- * network taps in order to match in-driver-XDP behavior.
+ * network taps in order to match in-driver-XDP behavior. This also means
+ * that XDP packets are able to starve other packets going through a qdisc,
+ * and DDOS attacks will be more effective. In-driver-XDP use dedicated TX
+ * queues, so they do not have this starvation issue.
*/
void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog)
{
@@ -4875,7 +4878,7 @@ void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog)
txq = netdev_core_pick_tx(dev, skb, NULL);
cpu = smp_processor_id();
HARD_TX_LOCK(dev, txq, cpu);
- if (!netif_xmit_stopped(txq)) {
+ if (!netif_xmit_frozen_or_drv_stopped(txq)) {
rc = netdev_start_xmit(skb, dev, txq, 0);
if (dev_xmit_complete(rc))
free_skb = false;
@@ -4883,6 +4886,7 @@ void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog)
HARD_TX_UNLOCK(dev, txq);
if (free_skb) {
trace_xdp_exception(dev, xdp_prog, XDP_TX);
+ dev_core_stats_tx_dropped_inc(dev);
kfree_skb(skb);
}
}