Re: [PATCH net-next v3 3/5] net: gso: support bounded TCP segmentation

Wang Zhan wrote:

The bounded resegmentation added by the next patch splits an oversized TCP
GSO skb into several GSO skbs which fit the device limits.  That needs the
GSO engine to group several MSS segments into one output skb, so let
callers bound the number of MSS segments each output skb carries and pass
the bound through the existing __skb_gso_segment() entry point.  Ordinary
callers use zero for no limit.

Without a bound, skb_segment() groups several MSS into one output skb only
for a device which advertises NETIF_F_GSO_PARTIAL or for a skb with a
frag_list which can be split into uniform pieces, and falls back to one
segment per skb otherwise.  A caller which passes a bound asks for the
grouping regardless, so the block which makes that decision is skipped
when max_segs is set.  Callers which pass no bound keep it, and the bounded
path only runs for skbs which carry no frag_list.

The output stays a GSO skb: gso_size is the original MSS and gso_segs is
the number of MSS it holds, so a downstream device can still perform
ordinary TSO.  Store the bound in the existing skb_gso_cb scratch context,
alongside the call-local data_offset and mac_offset fields, so that the
segmentation methods keep their signature.  A zero max_segs value means
that no bound is active; it is not a persistent skb flag.

Assisted-by: LLM
Signed-off-by: Wang Zhan <redacted>

---
v3:
- drop the tcp_gso_segment() exception: the caller keeps the features
- cap the bound with GSO_MAX_SEGS instead of U16_MAX
- drop the reset of the field in the output skbs: every caller initializes it
- note in the kernel-doc that a bound is for TCP GSO skbs only
- note at the frag_list gate that a bound must not go with a frag_list skb
v2: https://lore.kernel.org/20260918084651.3022878-3-wang.zhan@smartx.com/ (local)
v1: https://lore.kernel.org/20260917063854.2011613-3-wang.zhan@smartx.com/ (local)

To me this comment confuses rather than helps.

For one, it refers to "the bound" without any context.

Probably just drop.