Re: [PATCH net-next v5 0/7] introduce DEFINE_FLEX() macro

Kees Cook
2023-09-12T16:16:51Z

On Tue, Sep 12, 2023 at 07:59:30AM -0400, Przemek Kitszel wrote:
> Add DEFINE_FLEX() macro, that helps on-stack allocation of structures
> with trailing flex array member.
> Expose __struct_size() macro which reads size of data allocated
> by DEFINE_FLEX().
>
> Accompany new macros introduction with actual usage,
> in the ice driver - hence targeting for netdev tree.
>
> Obvious benefits include simpler resulting code, less heap usage,
> less error checking. Less obvious is the fact that compiler has
> more room to optimize, and as a whole, even with more stuff on the stack,
> we end up with overall better (smaller) report from bloat-o-meter:
> add/remove: 8/6 grow/shrink: 7/18 up/down: 2211/-2270 (-59)
> (individual results in each patch).
>
> v5: same as v4, just not RFC
> v4: _Static_assert() to ensure compiletime const count param
> v3: tidy up 1st patch
> v2: Kees: reusing __struct_size() instead of doubling it as a new macro
>
> Przemek Kitszel (7):
> overflow: add DEFINE_FLEX() for on-stack allocs
> ice: ice_sched_remove_elems: replace 1 elem array param by u32
> ice: drop two params of ice_aq_move_sched_elems()
> ice: make use of DEFINE_FLEX() in ice_ddp.c
> ice: make use of DEFINE_FLEX() for struct ice_aqc_add_tx_qgrp
> ice: make use of DEFINE_FLEX() for struct ice_aqc_dis_txq_item
> ice: make use of DEFINE_FLEX() in ice_switch.c

Looks good to me! Feel free to pick up via netdev.

-Kees

--
Kees Cook