linux-toradex.git/net/core/dev.c, branch v6.19-rc2

net_sched: add qdisc_dequeue_drop() helper

2025-11-25T15:10:32+00:00

Some qdisc like cake, codel, fq_codel might drop packets
in their dequeue() method.

This is currently problematic because dequeue() runs with
the qdisc spinlock held. Freeing skbs can be extremely expensive.

Add qdisc_dequeue_drop() method and a new TCQ_F_DEQUEUE_DROPS
so that these qdiscs can opt-in to defer the skb frees
after the socket spinlock is released.

TCQ_F_DEQUEUE_DROPS is an attempt to not penalize other qdiscs
with an extra cache line miss.

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-14-edumazet@google.com
Signed-off-by: Paolo Abeni

net_sched: add tcf_kfree_skb_list() helper

2025-11-25T15:10:32+00:00

Using kfree_skb_list_reason() to free list of skbs from qdisc
operations seems wrong as each skb might have a different drop reason.

Cleanup __dev_xmit_skb() to call tcf_kfree_skb_list() once
in preparation of the following patch.

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-13-edumazet@google.com
Signed-off-by: Paolo Abeni

net: annotate a data-race in __dev_xmit_skb()

2025-11-25T15:10:32+00:00

q->limit is read locklessly, add a READ_ONCE().

Fixes: 100dfa74cad9 ("net: dev_queue_xmit() llist adoption")
Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-12-edumazet@google.com
Signed-off-by: Paolo Abeni

net: prefech skb->priority in __dev_xmit_skb()

2025-11-25T15:10:32+00:00

Most qdiscs need to read skb->priority at enqueue time().

In commit 100dfa74cad9 ("net: dev_queue_xmit() llist adoption")
I added a prefetch(next), lets add another one for the second
half of skb.

Note that skb->priority and skb->hash share a common cache line,
so this patch helps qdiscs needing both fields.

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-11-edumazet@google.com
Signed-off-by: Paolo Abeni

net: use qdisc_pkt_len_segs_init() in sch_handle_ingress()

2025-11-25T15:10:31+00:00

sch_handle_ingress() sets qdisc_skb_cb(skb)->pkt_len.

We also need to initialize qdisc_skb_cb(skb)->pkt_segs.

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-5-edumazet@google.com
Signed-off-by: Paolo Abeni

net_sched: initialize qdisc_skb_cb(skb)->pkt_segs in qdisc_pkt_len_init()

2025-11-25T15:10:31+00:00

qdisc_pkt_len_init() is currently initalizing qdisc_skb_cb(skb)->pkt_len.

Add qdisc_skb_cb(skb)->pkt_segs initialization and rename this function
to qdisc_pkt_len_segs_init().

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-4-edumazet@google.com
Signed-off-by: Paolo Abeni

net: init shinfo->gso_segs from qdisc_pkt_len_init()

2025-11-25T15:10:31+00:00

Qdisc use shinfo->gso_segs for their pkts stats in bstats_update(),
but this field needs to be initialized for SKB_GSO_DODGY users.

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-3-edumazet@google.com
Signed-off-by: Paolo Abeni

net_sched: make room for (struct qdisc_skb_cb)->pkt_segs

2025-11-25T15:10:31+00:00

Add a new u16 field, next to pkt_len : pkt_segs

This will cache shinfo->gso_segs to speed up qdisc deqeue().

Move slave_dev_queue_mapping at the end of qdisc_skb_cb,
and move three bits from tc_skb_cb :
- post_ct
- post_ct_snat
- post_ct_dnat

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20251121083256.674562-2-edumazet@google.com
Signed-off-by: Paolo Abeni

net: add prefetch() in skb_defer_free_flush()

2025-11-08T03:00:16+00:00

skb_defer_free_flush() is becoming more important these days.

Add a prefetch operation to reduce latency a bit on some
platforms like AMD EPYC 7B12.

On more recent cpus, a stall happens when reading skb_shinfo().
Avoiding it will require a more elaborate strategy.

Signed-off-by: Eric Dumazet 
Acked-by: Paolo Abeni 
Link: https://patch.msgid.link/20251106085500.2438951-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: Convert struct sockaddr to fixed-size "sa_data[14]"

2025-11-05T03:10:33+00:00

Revert struct sockaddr from flexible array to fixed 14-byte "sa_data",
to solve over 36,000 -Wflex-array-member-not-at-end warnings, since
struct sockaddr is embedded within many network structs.

With socket/proto sockaddr-based internal APIs switched to use struct
sockaddr_unsized, there should be no more uses of struct sockaddr that
depend on reading beyond the end of struct sockaddr::sa_data that might
trigger bounds checking.

Comparing an x86_64 "allyesconfig" vmlinux build before and after this
patch showed no new "ud1" instructions from CONFIG_UBSAN_BOUNDS nor any
new "field-spanning" memcpy CONFIG_FORTIFY_SOURCE instrumentations.

Cc: Gustavo A. R. Silva 
Signed-off-by: Kees Cook 
Link: https://patch.msgid.link/20251104002617.2752303-8-kees@kernel.org
Signed-off-by: Jakub Kicinski