MFC 299889,299890,299892

299889
    hyperv/vmbus: Simplify event processing

    While I'm here, remove useless comment and unnecessary return.

    MFC after:  1 week
    Sponsored by:       Microsoft OSTC
    Differential Revision:      https://reviews.freebsd.org/D6332

299890
    hyperv/vmbus: Simplify event processing

    For channel0, it will never be processed on event handling path,
    so there is no need to install it.  After skipping in the channel0
    installation, we could discard the channel0 check on event
    handling hot code path.

    MFC after:  1 week
    Sponsored by:       Microsoft OSTC
    Differential Revision:      https://reviews.freebsd.org/D6333

299892
    hyperv/vmbus: Fix event processing loop indentation.

    No functional changes.

    MFC after:  1 week
    Sponsored by:       Microsoft OSTC
    Differential Revision:      https://reviews.freebsd.org/D6334

2 files changed, 31 insertions, 26 deletions

diff --git a/sys/dev/hyperv/vmbus/hv_channel_mgmt.c b/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
index 00b54ed..b342948 100644
--- a/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
+++ b/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
@@ -186,7 +186,14 @@ vmbus_channel_process_offer(hv_vmbus_channel *new_channel)
 	 * Make sure this is a new offer
 	 */
 	mtx_lock(&hv_vmbus_g_connection.channel_lock);
-	hv_vmbus_g_connection.channels[relid] = new_channel;
+	if (relid == 0) {
+		/*
+		 * XXX channel0 will not be processed; skip it.
+		 */
+		printf("VMBUS: got channel0 offer\n");
+	} else {
+		hv_vmbus_g_connection.channels[relid] = new_channel;
+	}
 
 	TAILQ_FOREACH(channel, &hv_vmbus_g_connection.channel_anchor,
 	    list_entry) {
diff --git a/sys/dev/hyperv/vmbus/hv_connection.c b/sys/dev/hyperv/vmbus/hv_connection.c
index 0424b47..c3a28a0 100644
--- a/sys/dev/hyperv/vmbus/hv_connection.c
+++ b/sys/dev/hyperv/vmbus/hv_connection.c
@@ -303,7 +303,6 @@ hv_vmbus_on_events(int cpu)
 	int rel_id;
 	int maxdword;
 	hv_vmbus_synic_event_flags *event;
-	/* int maxdword = PAGE_SIZE >> 3; */
 
 	KASSERT(cpu <= mp_maxid, ("VMBUS: hv_vmbus_on_events: "
 	    "cpu out of range!"));
@@ -317,9 +316,12 @@ hv_vmbus_on_events(int cpu)
 		/*
 		 * receive size is 1/2 page and divide that by 4 bytes
 		 */
-		if (synch_test_and_clear_bit(0, &event->flags32[0]))
+		if (synch_test_and_clear_bit(0, &event->flags32[0])) {
 			recv_interrupt_page =
 			    hv_vmbus_g_connection.recv_interrupt_page;
+		} else {
+			return;
+		}
 	} else {
 		/*
 		 * On Host with Win8 or above, the event page can be
@@ -333,36 +335,32 @@ hv_vmbus_on_events(int cpu)
 	/*
 	 * Check events
 	 */
-	if (recv_interrupt_page != NULL) {
-	    for (dword = 0; dword < maxdword; dword++) {
-		if (recv_interrupt_page[dword]) {
-		    for (bit = 0; bit < HV_CHANNEL_DWORD_LEN; bit++) {
+	for (dword = 0; dword < maxdword; dword++) {
+		if (recv_interrupt_page[dword] == 0)
+			continue;
+
+	        for (bit = 0; bit < HV_CHANNEL_DWORD_LEN; bit++) {
 			if (synch_test_and_clear_bit(bit,
-			    (uint32_t *) &recv_interrupt_page[dword])) {
-			    rel_id = (dword << 5) + bit;
-			    if (rel_id == 0) {
-				/*
-				 * Special case -
-				 * vmbus channel protocol msg.
-				 */
-				continue;
-			    } else {
-				hv_vmbus_channel * channel = hv_vmbus_g_connection.channels[rel_id];
+			    (uint32_t *)&recv_interrupt_page[dword])) {
+				struct hv_vmbus_channel *channel;
+
+				rel_id = (dword << 5) + bit;
+				channel =
+				    hv_vmbus_g_connection.channels[rel_id];
+
 				/* if channel is closed or closing */
 				if (channel == NULL || channel->rxq == NULL)
 					continue;
 
-				if (channel->batched_reading)
-					hv_ring_buffer_read_begin(&channel->inbound);
-				taskqueue_enqueue_fast(channel->rxq, &channel->channel_task);
-			    }
+				if (channel->batched_reading) {
+					hv_ring_buffer_read_begin(
+					    &channel->inbound);
+				}
+				taskqueue_enqueue(channel->rxq,
+				    &channel->channel_task);
 			}
-		    }
-		}
-	    }
+	        }
 	}
-
-	return;
 }
 
 /**