RH7: scsi: netvsc: Use the vmbus function to calculate ring buffer pe…

…rcentage (corrected for 7.0|7.x)

hv-rhel7.x/hv/hyperv_net.h

@@ -194,6 +194,10 @@ struct net_device_context;
 
 extern u32 netvsc_ring_bytes;
 
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7,0))
+extern u32 netvsc_ring_reciprocal;
+#endif
+
 struct netvsc_device *netvsc_device_add(struct hv_device *device,
 					const struct netvsc_device_info *info);
 int netvsc_alloc_recv_comp_ring(struct netvsc_device *net_device, u32 q_idx);

hv-rhel7.x/hv/include/linux/hyperv.h

@@ -36,6 +36,9 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 #include <linux/interrupt.h>
+#if (RHEL_RELEASE_CODE > RHEL_RELEASE_VERSION(7, 0))
+#include <linux/reciprocal_div.h>
+#endif
 
 #define MAX_PAGE_BUFFER_COUNT				32
 #define MAX_MULTIPAGE_BUFFER_COUNT			32 /* 128K */
@@ -121,6 +124,9 @@ struct hv_ring_buffer {
 struct hv_ring_buffer_info {
 	struct hv_ring_buffer *ring_buffer;
 	u32 ring_size;			/* Include the shared header */
+#if (RHEL_RELEASE_CODE > RHEL_RELEASE_VERSION(7,0))
+	struct reciprocal_value ring_size_div10_reciprocal;
+#endif
 	spinlock_t ring_lock;
 
 	u32 ring_datasize;		/* < ring_size */
@@ -155,7 +161,18 @@ static inline u32 hv_get_bytes_to_write(const struct hv_ring_buffer_info *rbi)
 	return write;
 }
 
-/*
+#if (RHEL_RELEASE_CODE > RHEL_RELEASE_VERSION(7, 0))
+static inline u32 hv_get_avail_to_write_percent(const struct hv_ring_buffer_info *rbi)
+{
+	u32 avail_write = hv_get_bytes_to_write(rbi);
+
+	return reciprocal_divide(
+		(avail_write << 3) + (avail_write << 1),
+		rbi->ring_size_div10_reciprocal);
+}
+#endif
+
+	/*
  * VMBUS version is 32 bit entity broken up into
  * two 16 bit quantities: major_number. minor_number.
  *

hv-rhel7.x/hv/netvsc.c

@@ -35,6 +35,12 @@
 #include "hyperv_net.h"
 #include "netvsc_trace.h"
 
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7,0))
+#include <linux/reciprocal_div.h>
+#else
+#include <linux/hyperv.h>
+#endif
+
 /*
  * Switch the data path from the synthetic interface to the VF
  * interface.
@@ -631,6 +637,18 @@ void netvsc_device_remove(struct hv_device *device)
 #define RING_AVAIL_PERCENT_HIWATER 20
 #define RING_AVAIL_PERCENT_LOWATER 10
 
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7, 0))
+/*
+ * 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);
+}
+#endif
+
 static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
 					 u32 index)
 {
@@ -687,8 +705,16 @@ 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_get_avail_to_write_percent(&channel->outbound) >
-		     RING_AVAIL_PERCENT_HIWATER || queue_sends < 1)) {
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7, 0))
+			 (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
+			 queue_sends < 1))
+		{
+#else
+			(hv_get_avail_to_write_percent(&channel->outbound) >
+			 RING_AVAIL_PERCENT_HIWATER ||
+			 queue_sends < 1))
+		{
+#endif
 			netif_tx_wake_queue(txq);
 			ndev_ctx->eth_stats.wake_queue++;
 		}
@@ -804,7 +830,11 @@ static inline int netvsc_send_pkt(
 	struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
 	u64 req_id;
 	int ret;
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7, 0))
+	u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
+#else
 	u32 ring_avail = hv_get_avail_to_write_percent(&out_channel->outbound);
+#endif
 
 	nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
 	if (skb)

hv-rhel7.x/hv/netvsc_drv.c

@@ -46,6 +46,10 @@
 
 #include "hyperv_net.h"
 
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7, 0))
+#include <linux/reciprocal_div.h>
+#endif
+
 #define RING_SIZE_MIN	64
 #define RETRY_US_LO	5000
 #define RETRY_US_HI	10000
@@ -59,6 +63,10 @@ module_param(ring_size, uint, 0444);
 MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
 unsigned int netvsc_ring_bytes;
 
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7, 0))
+u32 netvsc_ring_reciprocal;
+#endif
+
 static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
 				NETIF_MSG_LINK | NETIF_MSG_IFUP |
 				NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR |
@@ -2222,6 +2230,9 @@ static int __init netvsc_drv_init(void)
 			ring_size);
 	}
 	netvsc_ring_bytes = ring_size * PAGE_SIZE;
+#if (RHEL_RELEASE_CODE == RHEL_RELEASE_VERSION(7, 0))
+	netvsc_ring_reciprocal = reciprocal_value(netvsc_ring_bytes);
+#endif
 
 	ret = vmbus_driver_register(&netvsc_drv);
 	if (ret)