[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>

6 files changed, 23 insertions, 57 deletions

diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index dc52b1fa218e..ed041189e764 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/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]);
diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c
index 9db30fb5caf2..9c084bc09bbd 100644
--- a/drivers/scsi/libsas/sas_event.c
+++ b/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;
diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index d81c3b1989f7..a435876f1f77 100644
--- a/drivers/scsi/libsas/sas_init.c
+++ b/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)
diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 0d43408196f9..7fe4eded2866 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/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,
diff --git a/drivers/scsi/libsas/sas_phy.c b/drivers/scsi/libsas/sas_phy.c
index e0f5018e9071..dcfd4a9105c5 100644
--- a/drivers/scsi/libsas/sas_phy.c
+++ b/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);
diff --git a/drivers/scsi/libsas/sas_port.c b/drivers/scsi/libsas/sas_port.c
index 42fd1f25b664..a47c7a75327b 100644
--- a/drivers/scsi/libsas/sas_port.c
+++ b/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);
 }