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>
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 9b72ebc..19dd142 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -382,17 +382,11 @@
*/
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 {
/*
@@ -400,35 +394,29 @@
* 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) {
+ unsigned int bit = relid % BITS_PER_LONG;
+ unsigned int dword = BIT_WORD(relid);
- process_chn_event(relid);
- }
+ if (sync_test_and_clear_bit(bit, recv_int_page + dword)) {
+ /* Special case - vmbus channel protocol msg */
+ if (relid == 0)
+ continue;
+
+ process_chn_event(relid);
}
}
}
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 8dee6b9..cefa996 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -77,8 +77,7 @@
/* Define synthetic interrupt controller flag constants. */
#define HV_EVENT_FLAGS_COUNT (256 * 8)
-#define HV_EVENT_FLAGS_BYTE_COUNT (256)
-#define HV_EVENT_FLAGS_DWORD_COUNT (256 / sizeof(u32))
+#define HV_EVENT_FLAGS_LONG_COUNT (256 / sizeof(unsigned long))
/* Define invalid partition identifier. */
#define HV_PARTITION_ID_INVALID ((u64)0x0)
@@ -151,8 +150,7 @@
/* Define the synthetic interrupt controller event flags format. */
union hv_synic_event_flags {
- u8 flags8[HV_EVENT_FLAGS_BYTE_COUNT];
- u32 flags32[HV_EVENT_FLAGS_DWORD_COUNT];
+ unsigned long flags[HV_EVENT_FLAGS_LONG_COUNT];
};
/* Define the synthetic interrupt flags page layout. */
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 33eb5fd..96e291c 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -931,10 +931,8 @@
(vmbus_proto_version == VERSION_WIN7)) {
/* Since we are a child, we only need to check bit 0 */
- if (sync_test_and_clear_bit(0,
- (unsigned long *) &event->flags32[0])) {
+ if (sync_test_and_clear_bit(0, event->flags))
handled = true;
- }
} else {
/*
* Our host is win8 or above. The signaling mechanism
