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Subject: Re: [PATCH] net: optimize cmpxchg in ip_idents_reserve
To:     Peter Zijlstra <peterz@infradead.org>,
        Shaokun Zhang <zhangshaokun@hisilicon.com>
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From:   Eric Dumazet <eric.dumazet@gmail.com>
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Date:   Fri, 17 Jan 2020 08:35:07 -0800
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On 1/17/20 4:32 AM, Peter Zijlstra wrote:

> 
> That's crazy, just accept that UBSAN is taking bonghits and ignore it.
> Use atomic_add_return() unconditionally.
> 

Yes, we might simply add a comment so that people do not bug us if
their compiler is too old.

/* If UBSAN reports an error there, please make sure your compiler
 * supports -fno-strict-overflow before reporting it.
 */
return atomic_add_return(segs + delta, p_id) - segs;