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Date:   Sun, 6 Feb 2022 22:52:13 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        "H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
        linux-api@vger.kernel.org,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Florian Weimer <fw@deneb.enyo.de>, David.Laight@aculab.com,
        carlos@redhat.com, Peter Oskolkov <posk@posk.io>,
        libc-coord@lists.openwall.com
Subject: Re: [RFC PATCH 3/3] rseq: extend struct rseq with numa node id
Message-ID: <YgBDDVZSZqID8L3R@hirez.programming.kicks-ass.net>
References: <20220203193853.21511-1-mathieu.desnoyers@efficios.com>
 <20220203193853.21511-3-mathieu.desnoyers@efficios.com>
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In-Reply-To: <20220203193853.21511-3-mathieu.desnoyers@efficios.com>
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On Thu, Feb 03, 2022 at 02:38:53PM -0500, Mathieu Desnoyers wrote:
> +static int rseq_reset_rseq_cpu_node_id(struct task_struct *t)
>  {
> -	u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED;
> +	u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED, node_id = 0;
>  
>  	/*
>  	 * Reset cpu_id_start to its initial state (0).
> @@ -124,6 +126,11 @@ static int rseq_reset_rseq_cpu_id(struct task_struct *t)
>  	 */
>  	if (put_user(cpu_id, &t->rseq->cpu_id))
>  		return -EFAULT;
> +	/*
> +	 * Reset node_id to its initial state (0).
> +	 */
> +	if (put_user(node_id, &t->rseq->node_id))
> +		return -EFAULT;

Why 0 vs -1 ?