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Subject: Re: svn commit: r333859 - head/sys/kern
To: Matt Macy <mmacy@FreeBSD.org>, src-committers@freebsd.org,
 svn-src-all@freebsd.org, svn-src-head@freebsd.org
References: <201805190509.w4J59Atx053545@repo.freebsd.org>
From: Eric van Gyzen <eric@vangyzen.net>
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Date: Mon, 21 May 2018 11:54:14 -0500
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On 05/19/2018 00:09, Matt Macy wrote:
> @@ -1663,16 +1655,18 @@ static int
>  umtxq_sleep_pi(struct umtx_q *uq, struct umtx_pi *pi, uint32_t owner,
>      const char *wmesg, struct abs_timeout *timo, bool shared)
>  {
> -	struct umtxq_chain *uc;
>  	struct thread *td, *td1;
>  	struct umtx_q *uq1;
>  	int error, pri;
> +#ifdef INVARIANTS
> +	struct umtxq_chain *uc;
>  
> +	uc = umtxq_getchain(&pi->pi_key);
> +#endif
>  	error = 0;
>  	td = uq->uq_thread;
>  	KASSERT(td == curthread, ("inconsistent uq_thread"));
> -	uc = umtxq_getchain(&uq->uq_key);
> -	UMTXQ_LOCKED_ASSERT(uc);
> +	UMTXQ_LOCKED_ASSERT(umtxq_getchain(&uq->uq_key));

Couldn't this line stay as it was?

	UMTXQ_LOCKED_ASSERT(uc);

With the current code, we're calling umtxq_getchain() once more than
necessary.  Also, the casual reader might be confused by calling it with
two different arguments.

Eric