From: Shaokun Zhang <zhangshao...@hisilicon.com>
Date: Sat, 16 May 2020 11:46:49 +0800
> From: Yuqi Jin <jiny...@huawei.com>
>
> Commit adb03115f459 ("net: get rid of an signed integer overflow in
> ip_idents_reserve()")
> used atomic_cmpxchg to replace "atomic_add_return" inside the function
> "ip_idents_reserve". The reason was to avoid UBSAN warning.
> However, this change has caused performance degrade and in GCC-8,
> fno-strict-overflow is now mapped to -fwrapv -fwrapv-pointer
> and signed integer overflow is now undefined by default at all
> optimization levels[1]. Moreover, it was a bug in UBSAN vs -fwrapv
> /-fno-strict-overflow, so Let's revert it safely.
>
> [1] https://gcc.gnu.org/gcc-8/changes.html
>
> Suggested-by: Peter Zijlstra <pet...@infradead.org>
> Suggested-by: Eric Dumazet <eduma...@google.com>
...
> Signed-off-by: Yuqi Jin <jiny...@huawei.com>
> Signed-off-by: Shaokun Zhang <zhangshao...@hisilicon.com>
Applied, thanks.
