Drivers: hv: vmbus: Support a vmbus API for efficiently sending page arrays

[firefly-linux-kernel-4.4.55.git] / drivers / hv / channel.c

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c76ffbe59f65539597f5ba0cb5b50265ef2f3b7d..18c4f23dacf1b24d6c0c94f13abcff2ccf769730 100644 (file)
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -683,6 +683,50 @@ int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 }
 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 
+/*
+ * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
+ * using a GPADL Direct packet type.
+ * The buffer includes the vmbus descriptor.
+ */
+int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
+                             struct vmbus_packet_mpb_array *desc,
+                             u32 desc_size,
+                             void *buffer, u32 bufferlen, u64 requestid)
+{
+       int ret;
+       u32 packetlen;
+       u32 packetlen_aligned;
+       struct kvec bufferlist[3];
+       u64 aligned_data = 0;
+       bool signal = false;
+
+       packetlen = desc_size + bufferlen;
+       packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+
+       /* Setup the descriptor */
+       desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
+       desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
+       desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
+       desc->length8 = (u16)(packetlen_aligned >> 3);
+       desc->transactionid = requestid;
+       desc->rangecount = 1;
+
+       bufferlist[0].iov_base = desc;
+       bufferlist[0].iov_len = desc_size;
+       bufferlist[1].iov_base = buffer;
+       bufferlist[1].iov_len = bufferlen;
+       bufferlist[2].iov_base = &aligned_data;
+       bufferlist[2].iov_len = (packetlen_aligned - packetlen);
+
+       ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
+
+       if (ret == 0 && signal)
+               vmbus_setevent(channel);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
+
 /*
  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
  * using a GPADL Direct packet type.