Re: [RFC net-next v4 0/7] introduce DEFINE_FLEX() macro

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 9/4/23 14:31, 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
> - please me know if it is best approach here?

I have put this question in each revision up to now,
but perhaps no one noticed it, so making it stand out.

> 
> 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).
> 
> 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
> 
>   drivers/net/ethernet/intel/ice/ice_common.c | 20 ++-----
>   drivers/net/ethernet/intel/ice/ice_ddp.c    | 39 ++++---------
>   drivers/net/ethernet/intel/ice/ice_lag.c    | 48 ++++------------
>   drivers/net/ethernet/intel/ice/ice_lib.c    | 23 ++------
>   drivers/net/ethernet/intel/ice/ice_sched.c  | 56 ++++++------------
>   drivers/net/ethernet/intel/ice/ice_sched.h  |  6 +-
>   drivers/net/ethernet/intel/ice/ice_switch.c | 63 +++++----------------
>   drivers/net/ethernet/intel/ice/ice_xsk.c    | 22 +++----
>   include/linux/compiler_types.h              | 32 +++++++----
>   include/linux/fortify-string.h              |  4 --
>   include/linux/overflow.h                    | 35 ++++++++++++
>   11 files changed, 130 insertions(+), 218 deletions(-)
> 
> 
> base-commit: bd6c11bc43c496cddfc6cf603b5d45365606dbd5