From a0c3998ea9684c86b3952b6ffc1f95058be17d89 Mon Sep 17 00:00:00 2001
From: Sepherosa Ziehau <sephe@FreeBSD.org>
Date: Wed, 27 Jul 2016 05:47:32 +0000
Subject: [PATCH] hyperv/vmbus: Initialize RX/TX bufring mutex at channel
 creation time

MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D7312
---
 sys/dev/hyperv/vmbus/hv_ring_buffer.c | 22 +++++++++++++---------
 sys/dev/hyperv/vmbus/vmbus_brvar.h    |  6 ++++--
 sys/dev/hyperv/vmbus/vmbus_chan.c     |  4 ++++
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/sys/dev/hyperv/vmbus/hv_ring_buffer.c b/sys/dev/hyperv/vmbus/hv_ring_buffer.c
index a8a936ff5c0..b8f507ed177 100644
--- a/sys/dev/hyperv/vmbus/hv_ring_buffer.c
+++ b/sys/dev/hyperv/vmbus/hv_ring_buffer.c
@@ -198,20 +198,24 @@ hv_ring_buffer_needsig_on_write(uint32_t old_write_location,
 /**
  * @brief Initialize the ring buffer.
  */
-int
+void
 hv_vmbus_ring_buffer_init(hv_vmbus_ring_buffer_info *ring_info, void *buffer,
     uint32_t buffer_len)
 {
-	memset(ring_info, 0, sizeof(hv_vmbus_ring_buffer_info));
-
 	ring_info->ring_buffer = buffer;
-	ring_info->ring_buffer->br_rindex = 0;
-	ring_info->ring_buffer->br_windex = 0;
-
 	ring_info->ring_data_size = buffer_len - sizeof(struct vmbus_bufring);
-	mtx_init(&ring_info->ring_lock, "vmbus ring buffer", NULL, MTX_SPIN);
+}
 
-	return (0);
+void
+vmbus_br_init(hv_vmbus_ring_buffer_info *ring_info)
+{
+	mtx_init(&ring_info->ring_lock, "vmbus_br", NULL, MTX_SPIN);
+}
+
+void
+vmbus_br_deinit(hv_vmbus_ring_buffer_info *ring_info)
+{
+	mtx_destroy(&ring_info->ring_lock);
 }
 
 /**
@@ -220,7 +224,7 @@ hv_vmbus_ring_buffer_init(hv_vmbus_ring_buffer_info *ring_info, void *buffer,
 void
 hv_ring_buffer_cleanup(hv_vmbus_ring_buffer_info *ring_info) 
 {
-	mtx_destroy(&ring_info->ring_lock);
+	/* Do nothing */
 }
 
 /**
diff --git a/sys/dev/hyperv/vmbus/vmbus_brvar.h b/sys/dev/hyperv/vmbus/vmbus_brvar.h
index 915d5fe23a9..a47584fe724 100644
--- a/sys/dev/hyperv/vmbus/vmbus_brvar.h
+++ b/sys/dev/hyperv/vmbus/vmbus_brvar.h
@@ -49,11 +49,13 @@ void	vmbus_br_sysctl_create(struct sysctl_ctx_list *ctx,
 	    struct sysctl_oid *br_tree, hv_vmbus_ring_buffer_info *br,
 	    const char *name);
 
-int			hv_vmbus_ring_buffer_init(
+void	vmbus_br_init(hv_vmbus_ring_buffer_info *ring_info);
+void	vmbus_br_deinit(hv_vmbus_ring_buffer_info *ring_info);
+
+void			hv_vmbus_ring_buffer_init(
 				hv_vmbus_ring_buffer_info	*ring_info,
 				void				*buffer,
 				uint32_t			buffer_len);
-
 void			hv_ring_buffer_cleanup(
 				hv_vmbus_ring_buffer_info	*ring_info);
 
diff --git a/sys/dev/hyperv/vmbus/vmbus_chan.c b/sys/dev/hyperv/vmbus/vmbus_chan.c
index 44f57cda2b9..4a6c490d46f 100644
--- a/sys/dev/hyperv/vmbus/vmbus_chan.c
+++ b/sys/dev/hyperv/vmbus/vmbus_chan.c
@@ -914,6 +914,8 @@ vmbus_chan_alloc(struct vmbus_softc *sc)
 	mtx_init(&chan->ch_subchan_lock, "vmbus subchan", NULL, MTX_DEF);
 	TAILQ_INIT(&chan->ch_subchans);
 	TASK_INIT(&chan->ch_detach_task, 0, vmbus_chan_detach_task, chan);
+	vmbus_br_init(&chan->ch_rxbr);
+	vmbus_br_init(&chan->ch_txbr);
 
 	return chan;
 }
@@ -926,6 +928,8 @@ vmbus_chan_free(struct vmbus_channel *chan)
 	/* TODO: asset no longer on the vmbus channel list */
 	hyperv_dmamem_free(&chan->ch_monprm_dma, chan->ch_monprm);
 	mtx_destroy(&chan->ch_subchan_lock);
+	vmbus_br_deinit(&chan->ch_rxbr);
+	vmbus_br_deinit(&chan->ch_txbr);
 	free(chan, M_DEVBUF);
 }