Eric Lee / smarc-ti-linux-kernel | Embedian Git Server

Commit 046c7911b224267062ab1caeabbf11bc46e9c152

Authored by K. Y. Srinivasan 2014-09-06 08:29:12 +0800

Committed by Greg Kroah-Hartman 2014-09-24 14:31:22 +0800

Exists in ti-lsk-linux-4.1.y and in 10 other branches

Drivers: hv: vmbus: Enable interrupt driven flow control

In win8 we have a feature that allows for interrupt driven flow management
for host/guest communication. For instance, if the host were blocked because
there was no space available in the ringbuffer, the host could request that the
guest send an interrupt when space becomes available in the ringbuffer (when
the guest drains the ringbuffer).

While this feature was implemented in the guest a while ago, we had not
advertised that the guest supported this feature. This patch advertises
the support to the host.

For pre-win8 hosts, this has no effect since the size of the ringbuffer
control structure has not changed and all changes have been backward
compatible - unused/reserved space has been used to implement this
feature.

In this version of the patch I have cleaned up the commit log based on
feedback from Greg KH.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 5 additions and 0 deletions Side-by-side Diff

drivers/hv/ring_buffer.c

drivers/hv/ring_buffer.c

Diff comments View file @ 046c791

...	...	@@ -361,6 +361,11 @@
361	361	ring_info->ring_buffer->read_index =
362	362	ring_info->ring_buffer->write_index = 0;
363	363
	364	+ /*
	365	+ * Set the feature bit for enabling flow control.
	366	+ */
	367	+ ring_info->ring_buffer->feature_bits.value = 1;
	368	+
364	369	ring_info->ring_size = buflen;
365	370	ring_info->ring_datasize = buflen - sizeof(struct hv_ring_buffer);
366	371