hyperv: Enable sendbuf mechanism on the send path

We send packets using a copy-free mechanism (this is the Guest to Host transport
via VMBUS). While this is obviously optimal for large packets,
it may not be optimal for small packets. Hyper-V host supports
a second mechanism for sending packets that is "copy based". We implement that
mechanism in this patch.

In this version of the patch I have addressed a comment from David Miller.

With this patch (and all of the other offload and VRSS patches), we are now able
to almost saturate a 10G interface between Linux VMs on Hyper-V
on different hosts - close to  9 Gbps as measured via iperf.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index d1f7826aa75f..4b7df5a5c966 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -140,6 +140,8 @@ struct hv_netvsc_packet {
         void *send_completion_ctx;
         void (*send_completion)(void *context);
 
+        u32 send_buf_index;
+
         /* This points to the memory after page_buf */
         struct rndis_message *rndis_msg;
 
@@ -582,6 +584,9 @@ struct nvsp_message {
 
 #define NETVSC_RECEIVE_BUFFER_SIZE              (1024*1024*16)  /* 16MB */
 #define NETVSC_RECEIVE_BUFFER_SIZE_LEGACY       (1024*1024*15)  /* 15MB */
+#define NETVSC_SEND_BUFFER_SIZE                 (1024 * 1024)   /* 1MB */
+#define NETVSC_INVALID_INDEX                    -1
+
 
 #define NETVSC_RECEIVE_BUFFER_ID                0xcafe
 
@@ -607,6 +612,15 @@ struct netvsc_device {
         u32 recv_section_cnt;
         struct nvsp_1_receive_buffer_section *recv_section;
 
+        /* Send buffer allocated by us */
+        void *send_buf;
+        u32 send_buf_size;
+        u32 send_buf_gpadl_handle;
+        u32 send_section_cnt;
+        u32 send_section_size;
+        unsigned long *send_section_map;
+        int map_words;
+
         /* Used for NetVSP initialization protocol */
         struct completion channel_init_wait;
         struct nvsp_message channel_init_pkt;