Re: [PATCH v2 10/22] fjes: tx_stall_task

[Yasuaki Ishimatsu <yasu.isimatu@gmail.com>]

Hi Izum-san,

On Wed, 24 Jun 2015 11:55:42 +0900
Taku Izumi <izumi.taku@jp.fujitsu.com> wrote:

> This patch adds tx_stall_task.
> When receiver's buffer is full, sender stops
> its tx queue. This task is used to monitor
> receiver's status and when receiver's buffer
> is avairable, it resumes tx queue.
> 
> Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
> ---
>  drivers/net/fjes/fjes.h      |  2 ++
>  drivers/net/fjes/fjes_main.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 65 insertions(+)
> 
> diff --git a/drivers/net/fjes/fjes.h b/drivers/net/fjes/fjes.h
> index 8e9899e..b04ea9d 100644
> --- a/drivers/net/fjes/fjes.h
> +++ b/drivers/net/fjes/fjes.h
> @@ -30,6 +30,7 @@
>  #define FJES_MAX_QUEUES		1
>  #define FJES_TX_RETRY_INTERVAL	(20 * HZ)
>  #define FJES_TX_RETRY_TIMEOUT	(100)
> +#define FJES_TX_TX_STALL_TIMEOUT	(FJES_TX_RETRY_INTERVAL / 2)
>  #define FJES_OPEN_ZONE_UPDATE_WAIT	(300) /* msec */
>  
>  /* board specific private data structure */
> @@ -52,6 +53,7 @@ struct fjes_adapter {
>  
>  	struct workqueue_struct *txrx_wq;
>  
> +	struct work_struct tx_stall_task;
>  	struct work_struct raise_intr_rxdata_task;
>  
>  	struct fjes_hw hw;
> diff --git a/drivers/net/fjes/fjes_main.c b/drivers/net/fjes/fjes_main.c
> index 735aa5e..f4c2445 100644
> --- a/drivers/net/fjes/fjes_main.c
> +++ b/drivers/net/fjes/fjes_main.c
> @@ -53,6 +53,7 @@ static int fjes_setup_resources(struct fjes_adapter *);
>  static void fjes_free_resources(struct fjes_adapter *);
>  static netdev_tx_t fjes_xmit_frame(struct sk_buff *, struct net_device *);
>  static void fjes_raise_intr_rxdata_task(struct work_struct *);
> +static void fjes_tx_stall_task(struct work_struct *);
>  static irqreturn_t fjes_intr(int, void*);
>  
>  static int fjes_acpi_add(struct acpi_device *);
> @@ -281,6 +282,7 @@ static int fjes_close(struct net_device *netdev)
>  	fjes_free_irq(adapter);
>  
>  	cancel_work_sync(&adapter->raise_intr_rxdata_task);
> +	cancel_work_sync(&adapter->tx_stall_task);
>  
>  	fjes_hw_wait_epstop(hw);
>  
> @@ -410,6 +412,61 @@ static void fjes_free_resources(struct fjes_adapter *adapter)
>  	}
>  }
>  
> +static void fjes_tx_stall_task(struct work_struct *work)
> +{
> +	struct fjes_adapter *adapter = container_of(work,
> +			struct fjes_adapter, tx_stall_task);
> +	struct fjes_hw *hw = &adapter->hw;
> +	struct net_device *netdev = adapter->netdev;
> +	enum ep_partner_status pstatus;
> +	int epid;
> +	int max_epid, my_epid;
> +	union ep_buffer_info *info;
> +	int all_queue_available;
> +	int i;
> +	int sendable;
> +
> +	if (((long)jiffies -
> +		(long)(netdev->trans_start)) > FJES_TX_TX_STALL_TIMEOUT) {
> +		netif_wake_queue(netdev);
> +		return;
> +	}
> +
> +	my_epid = hw->my_epid;
> +	max_epid = hw->max_epid;
> +

> +	for (i = 0; i < 5; i++) {

Why do you loop 5 times?

Thanks,
Yasuaki Ishimatsu

> +		all_queue_available = 1;
> +
> +		for (epid = 0; epid < max_epid; epid++) {
> +			if (my_epid == epid)
> +				continue;
> +
> +			pstatus = fjes_hw_get_partner_ep_status(hw, epid);
> +			sendable = (pstatus == EP_PARTNER_SHARED);
> +			if (!sendable)
> +				continue;
> +
> +			info = adapter->hw.ep_shm_info[epid].tx.info;
> +
> +			if (EP_RING_FULL(info->v1i.head, info->v1i.tail,
> +					 info->v1i.count_max)) {
> +				all_queue_available = 0;
> +				break;
> +			}
> +		}
> +
> +		if (all_queue_available) {
> +			netif_wake_queue(netdev);
> +			return;
> +		}
> +	}
> +
> +	usleep_range(50, 100);
> +
> +	queue_work(adapter->txrx_wq, &adapter->tx_stall_task);
> +}
> +
>  static void fjes_raise_intr_rxdata_task(struct work_struct *work)
>  {
>  	struct fjes_adapter *adapter = container_of(work,
> @@ -606,6 +663,10 @@ fjes_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
>  					netdev->trans_start = jiffies;
>  					netif_tx_stop_queue(cur_queue);
>  
> +					if (!work_pending(&adapter->tx_stall_task))
> +						queue_work(adapter->txrx_wq,
> +							   &adapter->tx_stall_task);
> +
>  					ret = NETDEV_TX_BUSY;
>  				}
>  			} else {
> @@ -690,6 +751,7 @@ static int fjes_probe(struct platform_device *plat_dev)
>  
>  	adapter->txrx_wq = create_workqueue(DRV_NAME "/txrx");
>  
> +	INIT_WORK(&adapter->tx_stall_task, fjes_tx_stall_task);
>  	INIT_WORK(&adapter->raise_intr_rxdata_task,
>  		  fjes_raise_intr_rxdata_task);
>  
> @@ -734,6 +796,7 @@ static int fjes_remove(struct platform_device *plat_dev)
>  	struct fjes_hw *hw = &adapter->hw;
>  
>  	cancel_work_sync(&adapter->raise_intr_rxdata_task);
> +	cancel_work_sync(&adapter->tx_stall_task);
>  	if (adapter->txrx_wq)
>  		destroy_workqueue(adapter->txrx_wq);
>  
> -- 
> 1.8.3.1
>