RE: [PATCH v3 2/3] Drivers: hv: rename sc_lock to the more generic lock

[KY Srinivasan]

> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx]
> Sent: Tuesday, January 20, 2015 7:45 AM
> To: KY Srinivasan; devel@xxxxxxxxxxxxxxxxxxxxxx
> Cc: Haiyang Zhang; linux-kernel@xxxxxxxxxxxxxxx; Dexuan Cui; Jason Wang;
> Radim Krčmář; Dan Carpenter
> Subject: [PATCH v3 2/3] Drivers: hv: rename sc_lock to the more generic lock
> 
> sc_lock spinlock in struct vmbus_channel is being used to not only protect
> the sc_list field, e.g. vmbus_open() function uses it to implement test-and-
> set access to the state field. Rename it to the more generic 'lock' and add the
> description.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Thanks Vitaly.
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>

> ---
>  drivers/hv/channel.c      |  6 +++---
>  drivers/hv/channel_mgmt.c | 10 +++++-----
>  include/linux/hyperv.h    |  7 ++++++-
>  3 files changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index
> 433f72a..8608ed1 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -73,14 +73,14 @@ int vmbus_open(struct vmbus_channel
> *newchannel, u32 send_ringbuffer_size,
>  	unsigned long flags;
>  	int ret, t, err = 0;
> 
> -	spin_lock_irqsave(&newchannel->sc_lock, flags);
> +	spin_lock_irqsave(&newchannel->lock, flags);
>  	if (newchannel->state == CHANNEL_OPEN_STATE) {
>  		newchannel->state = CHANNEL_OPENING_STATE;
>  	} else {
> -		spin_unlock_irqrestore(&newchannel->sc_lock, flags);
> +		spin_unlock_irqrestore(&newchannel->lock, flags);
>  		return -EINVAL;
>  	}
> -	spin_unlock_irqrestore(&newchannel->sc_lock, flags);
> +	spin_unlock_irqrestore(&newchannel->lock, flags);
> 
>  	newchannel->onchannel_callback = onchannelcallback;
>  	newchannel->channel_callback_context = context; diff --git
> a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index
> 01f2c2b..c6fdd74 100644
> --- a/drivers/hv/channel_mgmt.c
> +++ b/drivers/hv/channel_mgmt.c
> @@ -146,7 +146,7 @@ static struct vmbus_channel *alloc_channel(void)
>  		return NULL;
> 
>  	spin_lock_init(&channel->inbound_lock);
> -	spin_lock_init(&channel->sc_lock);
> +	spin_lock_init(&channel->lock);
> 
>  	INIT_LIST_HEAD(&channel->sc_list);
>  	INIT_LIST_HEAD(&channel->percpu_list);
> @@ -246,9 +246,9 @@ static void vmbus_process_rescind_offer(struct
> work_struct *work)
>  		spin_unlock_irqrestore(&vmbus_connection.channel_lock,
> flags);
>  	} else {
>  		primary_channel = channel->primary_channel;
> -		spin_lock_irqsave(&primary_channel->sc_lock, flags);
> +		spin_lock_irqsave(&primary_channel->lock, flags);
>  		list_del(&channel->sc_list);
> -		spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
> +		spin_unlock_irqrestore(&primary_channel->lock, flags);
>  	}
>  	free_channel(channel);
>  }
> @@ -323,9 +323,9 @@ static void vmbus_process_offer(struct work_struct
> *work)
>  			 * Process the sub-channel.
>  			 */
>  			newchannel->primary_channel = channel;
> -			spin_lock_irqsave(&channel->sc_lock, flags);
> +			spin_lock_irqsave(&channel->lock, flags);
>  			list_add_tail(&newchannel->sc_list, &channel-
> >sc_list);
> -			spin_unlock_irqrestore(&channel->sc_lock, flags);
> +			spin_unlock_irqrestore(&channel->lock, flags);
> 
>  			if (newchannel->target_cpu != get_cpu()) {
>  				put_cpu();
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index
> 476c685..02dd978 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -722,7 +722,12 @@ struct vmbus_channel {
>  	 */
>  	void (*sc_creation_callback)(struct vmbus_channel *new_sc);
> 
> -	spinlock_t sc_lock;
> +	/*
> +	 * The spinlock to protect the structure. It is being used to protect
> +	 * test-and-set access to various attributes of the structure as well
> +	 * as all sc_list operations.
> +	 */
> +	spinlock_t lock;
>  	/*
>  	 * All Sub-channels of a primary channel are linked here.
>  	 */
> --
> 1.9.3

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