hyperv/vmbus: Initialize RX/TX bufring mutex at channel creation time

head/sys/dev/hyperv/vmbus/hv_ring_buffer.c

if (old_write_location == rbi->ring_buffer->br_rindex)
                 return (TRUE);
 
         return (FALSE);
 }
 
 /**
  * @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);
+}
+
 /**
  * @brief Cleanup the ring buffer.
  */
 void
 hv_ring_buffer_cleanup(hv_vmbus_ring_buffer_info *ring_info) 
 {
-        mtx_destroy(&ring_info->ring_lock);
+        /* Do nothing */
 }
 
 /**
  * @brief Write to the ring buffer.
  */
 int
 hv_ring_buffer_write(hv_vmbus_ring_buffer_info *out_ring_info,
     const struct iovec iov[], uint32_t iovlen, boolean_t *need_sig)

head/sys/dev/hyperv/vmbus/vmbus_brvar.h

 
 struct sysctl_ctx_list;
 struct sysctl_oid;
 
 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);
 
 int                     hv_ring_buffer_write(
                                 hv_vmbus_ring_buffer_info       *ring_info,
                                 const struct iovec              iov[],
                                 uint32_t                        iovlen,
                                 boolean_t                       *need_sig);

head/sys/dev/hyperv/vmbus/vmbus_chan.c

if (chan->ch_monprm == NULL) {
                 free(chan, M_DEVBUF);
                 return NULL;
         }
 
         chan->ch_vmbus = 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;
 }
 
 static void
 vmbus_chan_free(struct vmbus_channel *chan)
 {
         /* TODO: assert sub-channel list is empty */
         /* TODO: asset no longer on the primary channel's sub-channel list */
         /* 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);
 }
 
 static int
 vmbus_chan_add(struct vmbus_channel *newchan)
 {
         struct vmbus_softc *sc = newchan->ch_vmbus;
         struct vmbus_channel *prichan;