isci: cleanup/optimize queue increment macros
Every single i/o or event completion incurs a test and branch to see if
the cycle bit changed. For power-of-2 queue sizes the cycle bit can be
read directly from the rollover of the queue pointer.
Likely premature optimization, but the hidden if() and hidden
assignments / side-effects in the macros were already asking to be
cleaned up.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/scsi/isci/host.c b/drivers/scsi/isci/host.c
index 3c7042b..ae9edae 100644
--- a/drivers/scsi/isci/host.c
+++ b/drivers/scsi/isci/host.c
@@ -123,34 +123,6 @@
)
/**
- * INCREMENT_COMPLETION_QUEUE_GET() -
- *
- * This macro will increment the controllers completion queue index value and
- * possibly toggle the cycle bit if the completion queue index wraps back to 0.
- */
-#define INCREMENT_COMPLETION_QUEUE_GET(controller, index, cycle) \
- INCREMENT_QUEUE_GET(\
- (index), \
- (cycle), \
- SCU_MAX_COMPLETION_QUEUE_ENTRIES, \
- SMU_CQGR_CYCLE_BIT)
-
-/**
- * INCREMENT_EVENT_QUEUE_GET() -
- *
- * This macro will increment the controllers event queue index value and
- * possibly toggle the event cycle bit if the event queue index wraps back to 0.
- */
-#define INCREMENT_EVENT_QUEUE_GET(controller, index, cycle) \
- INCREMENT_QUEUE_GET(\
- (index), \
- (cycle), \
- SCU_MAX_EVENTS, \
- SMU_CQGR_EVENT_CYCLE_BIT \
- )
-
-
-/**
* NORMALIZE_GET_POINTER() -
*
* This macro will normalize the completion queue get pointer so its value can
@@ -528,15 +500,13 @@
}
}
-
-
static void scic_sds_controller_process_completions(struct scic_sds_controller *scic)
{
u32 completion_count = 0;
u32 completion_entry;
u32 get_index;
u32 get_cycle;
- u32 event_index;
+ u32 event_get;
u32 event_cycle;
dev_dbg(scic_to_dev(scic),
@@ -548,7 +518,7 @@
get_index = NORMALIZE_GET_POINTER(scic->completion_queue_get);
get_cycle = SMU_CQGR_CYCLE_BIT & scic->completion_queue_get;
- event_index = NORMALIZE_EVENT_POINTER(scic->completion_queue_get);
+ event_get = NORMALIZE_EVENT_POINTER(scic->completion_queue_get);
event_cycle = SMU_CQGR_EVENT_CYCLE_BIT & scic->completion_queue_get;
while (
@@ -558,7 +528,11 @@
completion_count++;
completion_entry = scic->completion_queue[get_index];
- INCREMENT_COMPLETION_QUEUE_GET(scic, get_index, get_cycle);
+
+ /* increment the get pointer and check for rollover to toggle the cycle bit */
+ get_cycle ^= ((get_index+1) & SCU_MAX_COMPLETION_QUEUE_ENTRIES) <<
+ (SMU_COMPLETION_QUEUE_GET_CYCLE_BIT_SHIFT - SCU_MAX_COMPLETION_QUEUE_SHIFT);
+ get_index = (get_index+1) & (SCU_MAX_COMPLETION_QUEUE_ENTRIES-1);
dev_dbg(scic_to_dev(scic),
"%s: completion queue entry:0x%08x\n",
@@ -579,18 +553,14 @@
break;
case SCU_COMPLETION_TYPE_EVENT:
- INCREMENT_EVENT_QUEUE_GET(scic, event_index, event_cycle);
+ case SCU_COMPLETION_TYPE_NOTIFY: {
+ event_cycle ^= ((event_get+1) & SCU_MAX_EVENTS) <<
+ (SMU_COMPLETION_QUEUE_GET_EVENT_CYCLE_BIT_SHIFT - SCU_MAX_EVENTS_SHIFT);
+ event_get = (event_get+1) & (SCU_MAX_EVENTS-1);
+
scic_sds_controller_event_completion(scic, completion_entry);
break;
-
- case SCU_COMPLETION_TYPE_NOTIFY:
- /*
- * Presently we do the same thing with a notify event that we do with the
- * other event codes. */
- INCREMENT_EVENT_QUEUE_GET(scic, event_index, event_cycle);
- scic_sds_controller_event_completion(scic, completion_entry);
- break;
-
+ }
default:
dev_warn(scic_to_dev(scic),
"%s: SCIC Controller received unknown "
@@ -607,7 +577,7 @@
SMU_CQGR_GEN_BIT(ENABLE) |
SMU_CQGR_GEN_BIT(EVENT_ENABLE) |
event_cycle |
- SMU_CQGR_GEN_VAL(EVENT_POINTER, event_index) |
+ SMU_CQGR_GEN_VAL(EVENT_POINTER, event_get) |
get_cycle |
SMU_CQGR_GEN_VAL(POINTER, get_index);