RE: [PATCH 2/3] Netvsc: Use the vmbus functiton to calculate ring buffer percentage

[Haiyang Zhang]

> -----Original Message-----
> From: Long Li <longli@xxxxxxxxxxxxxxxxx>
> Sent: Thursday, March 22, 2018 8:16 PM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>;
> James E . J . Bottomley <JBottomley@xxxxxxxx>; Martin K . Petersen
> <martin.petersen@xxxxxxxxxx>; devel@xxxxxxxxxxxxxxxxxxxxxx; linux-
> scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Long Li <longli@xxxxxxxxxxxxx>
> Subject: [PATCH 2/3] Netvsc: Use the vmbus functiton to calculate ring buffer
> percentage
> 
> From: Long Li <longli@xxxxxxxxxxxxx>
> 
> In Vmbus, we have defined a function to calculate available ring buffer
> percentage to write.
> 
> Use that function and remove duplicate netvsc code.
> 
> Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
> ---
>  drivers/net/hyperv/netvsc.c     | 17 +++--------------
>  drivers/net/hyperv/netvsc_drv.c |  3 ---
>  2 files changed, 3 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index
> 0265d703eb03..8af0069e4d8c 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -31,7 +31,6 @@
>  #include <linux/vmalloc.h>
>  #include <linux/rtnetlink.h>
>  #include <linux/prefetch.h>
> -#include <linux/reciprocal_div.h>
> 
>  #include <asm/sync_bitops.h>
> 
> @@ -590,17 +589,6 @@ void netvsc_device_remove(struct hv_device *device)
> #define RING_AVAIL_PERCENT_HIWATER 20  #define
> RING_AVAIL_PERCENT_LOWATER 10
> 
> -/*
> - * Get the percentage of available bytes to write in the ring.
> - * The return value is in range from 0 to 100.
> - */
> -static u32 hv_ringbuf_avail_percent(const struct hv_ring_buffer_info
> *ring_info) -{
> -	u32 avail_write = hv_get_bytes_to_write(ring_info);
> -
> -	return reciprocal_divide(avail_write  * 100, netvsc_ring_reciprocal);
> -}
> -
>  static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
>  					 u32 index)
>  {
> @@ -649,7 +637,8 @@ static void netvsc_send_tx_complete(struct
> netvsc_device *net_device,
>  		wake_up(&net_device->wait_drain);
> 
>  	if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
> -	    (hv_ringbuf_avail_percent(&channel->outbound) >
> RING_AVAIL_PERCENT_HIWATER ||
> +	    (hv_get_avail_to_write_percent(&channel->outbound) >
> +	     RING_AVAIL_PERCENT_HIWATER ||
>  	     queue_sends < 1)) {
>  		netif_tx_wake_queue(netdev_get_tx_queue(ndev, q_idx));
>  		ndev_ctx->eth_stats.wake_queue++;
> @@ -757,7 +746,7 @@ static inline int netvsc_send_pkt(
>  	struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
>  	u64 req_id;
>  	int ret;
> -	u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
> +	u32 ring_avail =
> +hv_get_avail_to_write_percent(&out_channel->outbound);
> 
>  	nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
>  	if (skb)
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index faea0be18924..b0b1c2fd2b7b 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -35,7 +35,6 @@
>  #include <linux/slab.h>
>  #include <linux/rtnetlink.h>
>  #include <linux/netpoll.h>
> -#include <linux/reciprocal_div.h>
> 
>  #include <net/arp.h>
>  #include <net/route.h>
> @@ -55,7 +54,6 @@ static unsigned int ring_size __ro_after_init = 128;
> module_param(ring_size, uint, S_IRUGO);  MODULE_PARM_DESC(ring_size,
> "Ring buffer size (# of pages)");  unsigned int netvsc_ring_bytes __ro_after_init;
> -struct reciprocal_value netvsc_ring_reciprocal __ro_after_init;
> 
>  static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
>  				NETIF_MSG_LINK | NETIF_MSG_IFUP |
> @@ -2186,7 +2184,6 @@ static int __init netvsc_drv_init(void)
>  			ring_size);
>  	}
>  	netvsc_ring_bytes = ring_size * PAGE_SIZE;
> -	netvsc_ring_reciprocal = reciprocal_value(netvsc_ring_bytes);
> 
>  	ret = vmbus_driver_register(&netvsc_drv);
>  	if (ret)
> --


Please also remove netvsc_ring_reciprocal from hyperv_net.h
Thanks.

Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>