[SCSI] libsas: replace event locks with atomic bitops

The locks only served to make sure the pending event bitmask was updated
consistently.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/libsas/sas_discover.c

@@ -295,8 +295,7 @@ static void sas_discover_domain(struct work_struct *work)
 		container_of(work, struct sas_discovery_event, work);
 	struct asd_sas_port *port = ev->port;
 
-	sas_begin_event(DISCE_DISCOVER_DOMAIN, &port->disc.disc_event_lock,
-			&port->disc.pending);
+	clear_bit(DISCE_DISCOVER_DOMAIN, &port->disc.pending);
 
 	if (port->port_dev)
 		return;
@@ -355,8 +354,7 @@ static void sas_revalidate_domain(struct work_struct *work)
 		container_of(work, struct sas_discovery_event, work);
 	struct asd_sas_port *port = ev->port;
 
-	sas_begin_event(DISCE_REVALIDATE_DOMAIN, &port->disc.disc_event_lock,
-			&port->disc.pending);
+	clear_bit(DISCE_REVALIDATE_DOMAIN, &port->disc.pending);
 
 	SAS_DPRINTK("REVALIDATING DOMAIN on port %d, pid:%d\n", port->id,
 		    task_pid_nr(current));
@@ -379,8 +377,7 @@ int sas_discover_event(struct asd_sas_port *port, enum discover_event ev)
 
 	BUG_ON(ev >= DISC_NUM_EVENTS);
 
-	sas_queue_event(ev, &disc->disc_event_lock, &disc->pending,
-			&disc->disc_work[ev].work, port->ha);
+	sas_queue_event(ev, &disc->pending, &disc->disc_work[ev].work, port->ha);
 
 	return 0;
 }
@@ -400,7 +397,6 @@ void sas_init_disc(struct sas_discovery *disc, struct asd_sas_port *port)
 		[DISCE_REVALIDATE_DOMAIN] = sas_revalidate_domain,
 	};
 
-	spin_lock_init(&disc->disc_event_lock);
 	disc->pending = 0;
 	for (i = 0; i < DISC_NUM_EVENTS; i++) {
 		INIT_WORK(&disc->disc_work[i].work, sas_event_fns[i]);

drivers/scsi/libsas/sas_event.c

@@ -30,7 +30,7 @@ static void notify_ha_event(struct sas_ha_struct *sas_ha, enum ha_event event)
 {
 	BUG_ON(event >= HA_NUM_EVENTS);
 
-	sas_queue_event(event, &sas_ha->event_lock, &sas_ha->pending,
+	sas_queue_event(event, &sas_ha->pending,
 			&sas_ha->ha_events[event].work, sas_ha);
 }
 
@@ -40,7 +40,7 @@ static void notify_port_event(struct asd_sas_phy *phy, enum port_event event)
 
 	BUG_ON(event >= PORT_NUM_EVENTS);
 
-	sas_queue_event(event, &ha->event_lock, &phy->port_events_pending,
+	sas_queue_event(event, &phy->port_events_pending,
 			&phy->port_events[event].work, ha);
 }
 
@@ -50,7 +50,7 @@ static void notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
 
 	BUG_ON(event >= PHY_NUM_EVENTS);
 
-	sas_queue_event(event, &ha->event_lock, &phy->phy_events_pending,
+	sas_queue_event(event, &phy->phy_events_pending,
 			&phy->phy_events[event].work, ha);
 }
 
@@ -62,8 +62,6 @@ int sas_init_events(struct sas_ha_struct *sas_ha)
 
 	int i;
 
-	spin_lock_init(&sas_ha->event_lock);
-
 	for (i = 0; i < HA_NUM_EVENTS; i++) {
 		INIT_WORK(&sas_ha->ha_events[i].work, sas_ha_event_fns[i]);
 		sas_ha->ha_events[i].ha = sas_ha;

drivers/scsi/libsas/sas_init.c

@@ -97,8 +97,7 @@ void sas_hae_reset(struct work_struct *work)
 		container_of(work, struct sas_ha_event, work);
 	struct sas_ha_struct *ha = ev->ha;
 
-	sas_begin_event(HAE_RESET, &ha->event_lock,
-			&ha->pending);
+	clear_bit(HAE_RESET, &ha->pending);
 }
 
 int sas_register_ha(struct sas_ha_struct *sas_ha)

drivers/scsi/libsas/sas_internal.h

@@ -92,36 +92,18 @@ static inline int sas_smp_host_handler(struct Scsi_Host *shost,
 }
 #endif
 
-static inline void sas_queue_event(int event, spinlock_t *lock,
-				   unsigned long *pending,
+static inline void sas_queue_event(int event, unsigned long *pending,
 				   struct work_struct *work,
 				   struct sas_ha_struct *sas_ha)
 {
-	unsigned long flags;
+	if (!test_and_set_bit(event, pending)) {
+		unsigned long flags;
 
-	spin_lock_irqsave(lock, flags);
-	if (test_bit(event, pending)) {
-		spin_unlock_irqrestore(lock, flags);
-		return;
+		spin_lock_irqsave(&sas_ha->state_lock, flags);
+		if (sas_ha->state != SAS_HA_UNREGISTERED)
+			scsi_queue_work(sas_ha->core.shost, work);
+		spin_unlock_irqrestore(&sas_ha->state_lock, flags);
 	}
-	__set_bit(event, pending);
-	spin_unlock_irqrestore(lock, flags);
-
-	spin_lock_irqsave(&sas_ha->state_lock, flags);
-	if (sas_ha->state != SAS_HA_UNREGISTERED) {
-		scsi_queue_work(sas_ha->core.shost, work);
-	}
-	spin_unlock_irqrestore(&sas_ha->state_lock, flags);
-}
-
-static inline void sas_begin_event(int event, spinlock_t *lock,
-				   unsigned long *pending)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(lock, flags);
-	__clear_bit(event, pending);
-	spin_unlock_irqrestore(lock, flags);
 }
 
 static inline void sas_fill_in_rphy(struct domain_device *dev,

drivers/scsi/libsas/sas_phy.c

@@ -36,8 +36,7 @@ static void sas_phye_loss_of_signal(struct work_struct *work)
 		container_of(work, struct asd_sas_event, work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	sas_begin_event(PHYE_LOSS_OF_SIGNAL, &phy->ha->event_lock,
-			&phy->phy_events_pending);
+	clear_bit(PHYE_LOSS_OF_SIGNAL, &phy->phy_events_pending);
 	phy->error = 0;
 	sas_deform_port(phy, 1);
 }
@@ -48,8 +47,7 @@ static void sas_phye_oob_done(struct work_struct *work)
 		container_of(work, struct asd_sas_event, work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	sas_begin_event(PHYE_OOB_DONE, &phy->ha->event_lock,
-			&phy->phy_events_pending);
+	clear_bit(PHYE_OOB_DONE, &phy->phy_events_pending);
 	phy->error = 0;
 }
 
@@ -63,8 +61,7 @@ static void sas_phye_oob_error(struct work_struct *work)
 	struct sas_internal *i =
 		to_sas_internal(sas_ha->core.shost->transportt);
 
-	sas_begin_event(PHYE_OOB_ERROR, &phy->ha->event_lock,
-			&phy->phy_events_pending);
+	clear_bit(PHYE_OOB_ERROR, &phy->phy_events_pending);
 
 	sas_deform_port(phy, 1);
 
@@ -95,8 +92,7 @@ static void sas_phye_spinup_hold(struct work_struct *work)
 	struct sas_internal *i =
 		to_sas_internal(sas_ha->core.shost->transportt);
 
-	sas_begin_event(PHYE_SPINUP_HOLD, &phy->ha->event_lock,
-			&phy->phy_events_pending);
+	clear_bit(PHYE_SPINUP_HOLD, &phy->phy_events_pending);
 
 	phy->error = 0;
 	i->dft->lldd_control_phy(phy, PHY_FUNC_RELEASE_SPINUP_HOLD, NULL);

drivers/scsi/libsas/sas_port.c

@@ -213,8 +213,7 @@ void sas_porte_bytes_dmaed(struct work_struct *work)
 		container_of(work, struct asd_sas_event, work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	sas_begin_event(PORTE_BYTES_DMAED, &phy->ha->event_lock,
-			&phy->port_events_pending);
+	clear_bit(PORTE_BYTES_DMAED, &phy->port_events_pending);
 
 	sas_form_port(phy);
 }
@@ -227,8 +226,7 @@ void sas_porte_broadcast_rcvd(struct work_struct *work)
 	unsigned long flags;
 	u32 prim;
 
-	sas_begin_event(PORTE_BROADCAST_RCVD, &phy->ha->event_lock,
-			&phy->port_events_pending);
+	clear_bit(PORTE_BROADCAST_RCVD, &phy->port_events_pending);
 
 	spin_lock_irqsave(&phy->sas_prim_lock, flags);
 	prim = phy->sas_prim;
@@ -244,8 +242,7 @@ void sas_porte_link_reset_err(struct work_struct *work)
 		container_of(work, struct asd_sas_event, work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	sas_begin_event(PORTE_LINK_RESET_ERR, &phy->ha->event_lock,
-			&phy->port_events_pending);
+	clear_bit(PORTE_LINK_RESET_ERR, &phy->port_events_pending);
 
 	sas_deform_port(phy, 1);
 }
@@ -256,8 +253,7 @@ void sas_porte_timer_event(struct work_struct *work)
 		container_of(work, struct asd_sas_event, work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	sas_begin_event(PORTE_TIMER_EVENT, &phy->ha->event_lock,
-			&phy->port_events_pending);
+	clear_bit(PORTE_TIMER_EVENT, &phy->port_events_pending);
 
 	sas_deform_port(phy, 1);
 }
@@ -268,8 +264,7 @@ void sas_porte_hard_reset(struct work_struct *work)
 		container_of(work, struct asd_sas_event, work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	sas_begin_event(PORTE_HARD_RESET, &phy->ha->event_lock,
-			&phy->port_events_pending);
+	clear_bit(PORTE_HARD_RESET, &phy->port_events_pending);
 
 	sas_deform_port(phy, 1);
 }

include/scsi/libsas.h

@@ -215,7 +215,6 @@ struct sas_discovery_event {
 };
 
 struct sas_discovery {
-	spinlock_t disc_event_lock;
 	struct sas_discovery_event disc_work[DISC_NUM_EVENTS];
 	unsigned long    pending;
 	u8     fanout_sas_addr[8];
@@ -272,7 +271,6 @@ struct asd_sas_event {
  */
 struct asd_sas_phy {
 /* private: */
-	/* protected by ha->event_lock */
 	struct asd_sas_event   port_events[PORT_NUM_EVENTS];
 	struct asd_sas_event   phy_events[PHY_NUM_EVENTS];
 
@@ -337,7 +335,6 @@ enum sas_ha_state {
 
 struct sas_ha_struct {
 /* private: */
-	spinlock_t       event_lock;
 	struct sas_ha_event ha_events[HA_NUM_EVENTS];
 	unsigned long	 pending;