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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Colin King <colin.king@canonical.com>
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
        "K . Y . Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, linux-hyperv@vger.kernel.org
Subject: Re: [PATCH][next] drivers: hv: remove redundant assignment to pointer primary_channel
In-Reply-To: <20200414152343.243166-1-colin.king@canonical.com>
References: <20200414152343.243166-1-colin.king@canonical.com>
Date:   Tue, 14 Apr 2020 18:51:11 +0200
Message-ID: <87d08axb7k.fsf@vitty.brq.redhat.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Colin King <colin.king@canonical.com> writes:

> From: Colin Ian King <colin.king@canonical.com>
>
> The pointer primary_channel is being assigned with a value that is never,
> The assignment is redundant and can be removed.
>
> Addresses-Coverity: ("Unused value")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/hv/channel_mgmt.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
> index ffd7fffa5f83..f7bbb8dc4b0f 100644
> --- a/drivers/hv/channel_mgmt.c
> +++ b/drivers/hv/channel_mgmt.c
> @@ -425,8 +425,6 @@ void hv_process_channel_removal(struct vmbus_channel *channel)
>  
>  	if (channel->primary_channel == NULL) {
>  		list_del(&channel->listentry);
> -
> -		primary_channel = channel;
>  	} else {
>  		primary_channel = channel->primary_channel;
>  		spin_lock_irqsave(&primary_channel->lock, flags);

If I'm looking at the right source (5.7-rc1) it *is* beeing used:

	if (channel->primary_channel == NULL) {
		list_del(&channel->listentry);

		primary_channel = channel;
	} else {
		primary_channel = channel->primary_channel;
		spin_lock_irqsave(&primary_channel->lock, flags);
		list_del(&channel->sc_list);
		spin_unlock_irqrestore(&primary_channel->lock, flags);
	}

	/*
	 * We need to free the bit for init_vp_index() to work in the case
	 * of sub-channel, when we reload drivers like hv_netvsc.
	 */
	if (channel->affinity_policy == HV_LOCALIZED)
		cpumask_clear_cpu(channel->target_cpu,
				  &primary_channel->alloced_cpus_in_node);
                                   ^^^^^ HERE ^^^^^

-- 
Vitaly