From: Long Li <longli@microsoft.com>
Date: Tue, 27 Mar 2018 17:48:39 -0700
Patch-mainline: v4.18-rc1
Subject: scsi: netvsc: Use the vmbus function to calculate ring buffer percentage
Git-commit: 6b1f8376dc34fb3b728672ed6e06751f26b3b225
References: bsc#1107207

In Vmbus, we have defined a function to calculate available ring buffer
percentage to write.

Use that function and remove netvsc's private version.

[mkp: typo]

Signed-off-by: Long Li <longli@microsoft.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/net/hyperv/hyperv_net.h |  1 -
 drivers/net/hyperv/netvsc.c     | 18 +++---------------
 drivers/net/hyperv/netvsc_drv.c |  3 ---
 3 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -189,7 +189,6 @@ struct netvsc_device;
 struct net_device_context;
 
 extern u32 netvsc_ring_bytes;
-extern struct reciprocal_value netvsc_ring_reciprocal;
 
 struct netvsc_device *netvsc_device_add(struct hv_device *device,
 					const struct netvsc_device_info *info);
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
--- 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>
 
@@ -634,17 +633,6 @@ 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)
 {
@@ -696,8 +684,8 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 		struct netdev_queue *txq = netdev_get_tx_queue(ndev, q_idx);
 
 		if (netif_tx_queue_stopped(txq) &&
-		    (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
-		     queue_sends < 1)) {
+		    (hv_get_avail_to_write_percent(&channel->outbound) >
+		     RING_AVAIL_PERCENT_HIWATER || queue_sends < 1)) {
 			netif_tx_wake_queue(txq);
 			ndev_ctx->eth_stats.wake_queue++;
 		}
@@ -805,7 +793,7 @@ 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
--- 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>
@@ -58,7 +58,6 @@ static unsigned int ring_size __ro_after
 module_param(ring_size, uint, 0444);
 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 |
@@ -2218,7 +2216,6 @@ 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)