vmbus: use kernel bitops for traversing interrupt mask

Use standard kernel operations for find first set bit to traverse
the channel bit array. This has added benefit of speeding up
lookup on 64 bit and because it uses find first set instruction.

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

1 files changed, 17 insertions, 38 deletions

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 307a5a8937f6..1766ef03e78d 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -379,17 +379,11 @@ static void process_chn_event(u32 relid)
  */
 void vmbus_on_event(unsigned long data)
 {
-	u32 dword;
-	u32 maxdword;
-	int bit;
-	u32 relid;
-	u32 *recv_int_page = NULL;
-	void *page_addr;
-	int cpu = smp_processor_id();
-	union hv_synic_event_flags *event;
+	unsigned long *recv_int_page;
+	u32 maxbits, relid;
 
 	if (vmbus_proto_version < VERSION_WIN8) {
-		maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
+		maxbits = MAX_NUM_CHANNELS_SUPPORTED;
 		recv_int_page = vmbus_connection.recv_int_page;
 	} else {
 		/*
@@ -397,35 +391,24 @@ void vmbus_on_event(unsigned long data)
 		 * can be directly checked to get the id of the channel
 		 * that has the interrupt pending.
 		 */
-		maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
-		page_addr = hv_context.synic_event_page[cpu];
-		event = (union hv_synic_event_flags *)page_addr +
+		int cpu = smp_processor_id();
+		void *page_addr = hv_context.synic_event_page[cpu];
+		union hv_synic_event_flags *event
+			= (union hv_synic_event_flags *)page_addr +
 						 VMBUS_MESSAGE_SINT;
-		recv_int_page = event->flags32;
-	}
-
 
+		maxbits = HV_EVENT_FLAGS_COUNT;
+		recv_int_page = event->flags;
+	}
 
-	/* Check events */
-	if (!recv_int_page)
+	if (unlikely(!recv_int_page))
 		return;
-	for (dword = 0; dword < maxdword; dword++) {
-		if (!recv_int_page[dword])
-			continue;
-		for (bit = 0; bit < 32; bit++) {
-			if (sync_test_and_clear_bit(bit,
-				(unsigned long *)&recv_int_page[dword])) {
-				relid = (dword << 5) + bit;
-
-				if (relid == 0)
-					/*
-					 * Special case - vmbus
-					 * channel protocol msg
-					 */
-					continue;
 
+	for_each_set_bit(relid, recv_int_page, maxbits) {
+		if (sync_test_and_clear_bit(relid, recv_int_page)) {
+			/* Special case - vmbus channel protocol msg */
+			if (relid != 0)
 				process_chn_event(relid);
-			}
 		}
 	}
 }
@@ -491,12 +474,8 @@ void vmbus_set_event(struct vmbus_channel *channel)
 {
 	u32 child_relid = channel->offermsg.child_relid;
 
-	if (!channel->is_dedicated_interrupt) {
-		/* Each u32 represents 32 channels */
-		sync_set_bit(child_relid & 31,
-			(unsigned long *)vmbus_connection.send_int_page +
-			(child_relid >> 5));
-	}
+	if (!channel->is_dedicated_interrupt)
+		vmbus_send_interrupt(child_relid);
 
 	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
 }