[SCSI] hpsa: only do device rescan for certain events

Do no rescan on every events -- way too many rescans are
triggered if we don't filter the events.  Limit rescans
to be triggered by the following set of events:

 * controller state change
 * enclosure hot plug
 * physical drive state change
 * logical drive state change
 * redundant controller state change
 * accelerated io enabled/disabled
 * accelerated io configuration change
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/hpsa.c

@@ -6419,7 +6419,7 @@ static void hpsa_ctlr_needs_rescan(struct ctlr_info *h)
 		return;
 
 	h->events = readl(&(h->cfgtable->event_notify));
-	if (!h->events && !h->drv_req_rescan)
+	if (!(h->events & RESCAN_REQUIRED_EVENT_BITS) && !h->drv_req_rescan)
 		return;
 
 	/*

drivers/scsi/hpsa.h

@@ -181,6 +181,22 @@ struct ctlr_info {
 #define HPSATMF_LOG_QRY_TSET    (1 << 24)
 #define HPSATMF_LOG_QRY_ASYNC   (1 << 25)
 	u32 events;
+#define CTLR_STATE_CHANGE_EVENT				(1 << 0)
+#define CTLR_ENCLOSURE_HOT_PLUG_EVENT			(1 << 1)
+#define CTLR_STATE_CHANGE_EVENT_PHYSICAL_DRV		(1 << 4)
+#define CTLR_STATE_CHANGE_EVENT_LOGICAL_DRV		(1 << 5)
+#define CTLR_STATE_CHANGE_EVENT_REDUNDANT_CNTRL		(1 << 6)
+#define CTLR_STATE_CHANGE_EVENT_AIO_ENABLED_DISABLED	(1 << 30)
+#define CTLR_STATE_CHANGE_EVENT_AIO_CONFIG_CHANGE	(1 << 31)
+
+#define RESCAN_REQUIRED_EVENT_BITS \
+		(CTLR_STATE_CHANGE_EVENT | \
+		CTLR_ENCLOSURE_HOT_PLUG_EVENT | \
+		CTLR_STATE_CHANGE_EVENT_PHYSICAL_DRV | \
+		CTLR_STATE_CHANGE_EVENT_LOGICAL_DRV | \
+		CTLR_STATE_CHANGE_EVENT_REDUNDANT_CNTRL | \
+		CTLR_STATE_CHANGE_EVENT_AIO_ENABLED_DISABLED | \
+		CTLR_STATE_CHANGE_EVENT_AIO_CONFIG_CHANGE)
 	int	acciopath_status;
 	int	drv_req_rescan;	/* flag for driver to request rescan event */
 };