Merge tag 'isci-for-3.5' into misc

isci update for 3.5

1/ Rework remote-node-context (RNC) handling for proper management of
   the silicon state machine in error handling and hot-plug conditions.
   Further details below, suffice to say if the RNC is mismanaged the
   silicon state machines may lock up.

2/ Refactor the initialization code to be reused for suspend/resume support

3/ Miscellaneous bug fixes to address discovery issues and hardware
   compatibility.

RNC rework details from Jeff Skirvin:

In the controller, devices as they appear on a SAS domain (or
direct-attached SATA devices) are represented by memory structures known
as "Remote Node Contexts" (RNCs).  These structures are transferred from
main memory to the controller using a set of register commands; these
commands include setting up the context ("posting"), removing the
context ("invalidating"), and commands to control the scheduling of
commands and connections to that remote device ("suspensions" and
"resumptions").  There is a similar path to control RNC scheduling from
the protocol engine, which interprets the results of command and data
transmission and reception.

In general, the controller chooses among non-suspended RNCs to find one
that has work requiring scheduling the transmission of command and data
frames to a target.  Likewise, when a target tries to return data back
to the initiator, the state of the RNC is used by the controller to
determine how to treat the incoming request. As an example, if the RNC
is in the state "TX/RX Suspended", incoming SSP connection requests from
the target will be rejected by the controller hardware.  When an RNC is
"TX Suspended", it will not be selected by the controller hardware to
start outgoing command or data operations (with certain priority-based
exceptions).

As mentioned above, there are two sources for management of the RNC
states: commands from driver software, and the result of transmission
and reception conditions of commands and data signaled by the controller
hardware.  As an example of the latter, if an outgoing SSP command ends
with a OPEN_REJECT(BAD_DESTINATION) status, the RNC state will
transition to the "TX Suspended" state, and this is signaled by the
controller hardware in the status to the completion of the pending
command as well as signaled in a controller hardware event.  Examples of
the former are included in the patch changelogs.

Driver software is required to suspend the RNC in a "TX/RX Suspended"
condition before any outstanding commands can be terminated.  Failure to
guarantee this can lead to a complete hardware hang condition.  Earlier
versions of the driver software did not guarantee that an RNC was
correctly managed before I/O termination, and so operated in an unsafe
way.

Further, the driver performed unnecessary contortions to preserve the
remote device command state and so was more complicated than it needed
to be.  A simplifying driver assumption is that once an I/O has entered
the error handler path without having completed in the target, the
requirement on the driver is that all use of the sas_task must end.
Beyond that, recovery of operation is dependent on libsas and other
components to reset, rediscover and reconfigure the device before normal
operation can restart.  In the driver, this simplifying assumption meant
that the RNC management could be reduced to entry into the suspended
state, terminating the targeted I/O request, and resuming the RNC as
needed for device-specific management such as an SSP Abort Task or LUN
Reset Management request.

1 files changed, 35 insertions, 26 deletions

diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index 364679675602..629a0865b130 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -72,6 +72,7 @@ static int sas_get_port_device(struct asd_sas_port *port)
 	struct asd_sas_phy *phy;
 	struct sas_rphy *rphy;
 	struct domain_device *dev;
+	int rc = -ENODEV;
 
 	dev = sas_alloc_device();
 	if (!dev)
@@ -110,9 +111,16 @@ static int sas_get_port_device(struct asd_sas_port *port)
 
 	sas_init_dev(dev);
 
+	dev->port = port;
 	switch (dev->dev_type) {
-	case SAS_END_DEV:
 	case SATA_DEV:
+		rc = sas_ata_init(dev);
+		if (rc) {
+			rphy = NULL;
+			break;
+		}
+		/* fall through */
+	case SAS_END_DEV:
 		rphy = sas_end_device_alloc(port->port);
 		break;
 	case EDGE_DEV:
@@ -131,19 +139,14 @@ static int sas_get_port_device(struct asd_sas_port *port)
 
 	if (!rphy) {
 		sas_put_device(dev);
-		return -ENODEV;
+		return rc;
 	}
 
-	spin_lock_irq(&port->phy_list_lock);
-	list_for_each_entry(phy, &port->phy_list, port_phy_el)
-		sas_phy_set_target(phy, dev);
-	spin_unlock_irq(&port->phy_list_lock);
 	rphy->identify.phy_identifier = phy->phy->identify.phy_identifier;
 	memcpy(dev->sas_addr, port->attached_sas_addr, SAS_ADDR_SIZE);
 	sas_fill_in_rphy(dev, rphy);
 	sas_hash_addr(dev->hashed_sas_addr, dev->sas_addr);
 	port->port_dev = dev;
-	dev->port = port;
 	dev->linkrate = port->linkrate;
 	dev->min_linkrate = port->linkrate;
 	dev->max_linkrate = port->linkrate;
@@ -155,6 +158,7 @@ static int sas_get_port_device(struct asd_sas_port *port)
 	sas_device_set_phy(dev, port->port);
 
 	dev->rphy = rphy;
+	get_device(&dev->rphy->dev);
 
 	if (dev_is_sata(dev) || dev->dev_type == SAS_END_DEV)
 		list_add_tail(&dev->disco_list_node, &port->disco_list);
@@ -164,6 +168,11 @@ static int sas_get_port_device(struct asd_sas_port *port)
 		spin_unlock_irq(&port->dev_list_lock);
 	}
 
+	spin_lock_irq(&port->phy_list_lock);
+	list_for_each_entry(phy, &port->phy_list, port_phy_el)
+		sas_phy_set_target(phy, dev);
+	spin_unlock_irq(&port->phy_list_lock);
+
 	return 0;
 }
 
@@ -205,8 +214,7 @@ void sas_notify_lldd_dev_gone(struct domain_device *dev)
 static void sas_probe_devices(struct work_struct *work)
 {
 	struct domain_device *dev, *n;
-	struct sas_discovery_event *ev =
-		container_of(work, struct sas_discovery_event, work);
+	struct sas_discovery_event *ev = to_sas_discovery_event(work);
 	struct asd_sas_port *port = ev->port;
 
 	clear_bit(DISCE_PROBE, &port->disc.pending);
@@ -255,6 +263,9 @@ void sas_free_device(struct kref *kref)
 {
 	struct domain_device *dev = container_of(kref, typeof(*dev), kref);
 
+	put_device(&dev->rphy->dev);
+	dev->rphy = NULL;
+
 	if (dev->parent)
 		sas_put_device(dev->parent);
 
@@ -291,8 +302,7 @@ static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_d
 static void sas_destruct_devices(struct work_struct *work)
 {
 	struct domain_device *dev, *n;
-	struct sas_discovery_event *ev =
-		container_of(work, struct sas_discovery_event, work);
+	struct sas_discovery_event *ev = to_sas_discovery_event(work);
 	struct asd_sas_port *port = ev->port;
 
 	clear_bit(DISCE_DESTRUCT, &port->disc.pending);
@@ -302,7 +312,6 @@ static void sas_destruct_devices(struct work_struct *work)
 
 		sas_remove_children(&dev->rphy->dev);
 		sas_rphy_delete(dev->rphy);
-		dev->rphy = NULL;
 		sas_unregister_common_dev(port, dev);
 	}
 }
@@ -314,11 +323,11 @@ void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
 		/* this rphy never saw sas_rphy_add */
 		list_del_init(&dev->disco_list_node);
 		sas_rphy_free(dev->rphy);
-		dev->rphy = NULL;
 		sas_unregister_common_dev(port, dev);
+		return;
 	}
 
-	if (dev->rphy && !test_and_set_bit(SAS_DEV_DESTROY, &dev->state)) {
+	if (!test_and_set_bit(SAS_DEV_DESTROY, &dev->state)) {
 		sas_rphy_unlink(dev->rphy);
 		list_move_tail(&dev->disco_list_node, &port->destroy_list);
 		sas_discover_event(dev->port, DISCE_DESTRUCT);
@@ -377,8 +386,7 @@ static void sas_discover_domain(struct work_struct *work)
 {
 	struct domain_device *dev;
 	int error = 0;
-	struct sas_discovery_event *ev =
-		container_of(work, struct sas_discovery_event, work);
+	struct sas_discovery_event *ev = to_sas_discovery_event(work);
 	struct asd_sas_port *port = ev->port;
 
 	clear_bit(DISCE_DISCOVER_DOMAIN, &port->disc.pending);
@@ -419,8 +427,6 @@ static void sas_discover_domain(struct work_struct *work)
 
 	if (error) {
 		sas_rphy_free(dev->rphy);
-		dev->rphy = NULL;
-
 		list_del_init(&dev->disco_list_node);
 		spin_lock_irq(&port->dev_list_lock);
 		list_del_init(&dev->dev_list_node);
@@ -437,8 +443,7 @@ static void sas_discover_domain(struct work_struct *work)
 static void sas_revalidate_domain(struct work_struct *work)
 {
 	int res = 0;
-	struct sas_discovery_event *ev =
-		container_of(work, struct sas_discovery_event, work);
+	struct sas_discovery_event *ev = to_sas_discovery_event(work);
 	struct asd_sas_port *port = ev->port;
 	struct sas_ha_struct *ha = port->ha;
 
@@ -466,21 +471,25 @@ static void sas_revalidate_domain(struct work_struct *work)
 
 /* ---------- Events ---------- */
 
-static void sas_chain_work(struct sas_ha_struct *ha, struct work_struct *work)
+static void sas_chain_work(struct sas_ha_struct *ha, struct sas_work *sw)
 {
-	/* chained work is not subject to SA_HA_DRAINING or SAS_HA_REGISTERED */
-	scsi_queue_work(ha->core.shost, work);
+	/* chained work is not subject to SA_HA_DRAINING or
+	 * SAS_HA_REGISTERED, because it is either submitted in the
+	 * workqueue, or known to be submitted from a context that is
+	 * not racing against draining
+	 */
+	scsi_queue_work(ha->core.shost, &sw->work);
 }
 
 static void sas_chain_event(int event, unsigned long *pending,
-			    struct work_struct *work,
+			    struct sas_work *sw,
 			    struct sas_ha_struct *ha)
 {
 	if (!test_and_set_bit(event, pending)) {
 		unsigned long flags;
 
 		spin_lock_irqsave(&ha->state_lock, flags);
-		sas_chain_work(ha, work);
+		sas_chain_work(ha, sw);
 		spin_unlock_irqrestore(&ha->state_lock, flags);
 	}
 }
@@ -519,7 +528,7 @@ void sas_init_disc(struct sas_discovery *disc, struct asd_sas_port *port)
 
 	disc->pending = 0;
 	for (i = 0; i < DISC_NUM_EVENTS; i++) {
-		INIT_WORK(&disc->disc_work[i].work, sas_event_fns[i]);
+		INIT_SAS_WORK(&disc->disc_work[i].work, sas_event_fns[i]);
 		disc->disc_work[i].port = port;
 	}
 }