[PATCH RESEND 10/10] Drivers: hv: vmbus: Permit sending of packets without payload

K. Y. Srinivasan
2015-06-28T17:40:12Z

The guest may have to send a completion packet back to the host.
To support this usage, permit sending a packet without a payload -
we would be only sending the descriptor in this case.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/channel.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 603ce97..c4dcab0 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -601,6 +601,7 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
u64 aligned_data = 0;
int ret;
bool signal = false;
+ int num_vecs = ((bufferlen != 0) ? 3 : 1);

/* Setup the descriptor */
@@ -618,7 +619,8 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
bufferlist[2].iov_base = &aligned_data;
bufferlist[2].iov_len = (packetlen_aligned - packetlen);

- ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
+ ret = hv_ringbuffer_write(&channel->outbound, bufferlist, num_vecs,
+ &signal);

/*
* Signalling the host is conditional on many factors:
--
1.7.4.1