libsas: Don't issue commands to devices that have been hot-removed

From: Darrick J. Wong <[email protected]>

sd will get hung up issuing commands to flush write cache if a SAS device behind the expander is unplugged without warning. Change libsas to reject commands to domain devices that have already gone away.

[[email protected]: removed setting ->gone in sas_deform_port() to
permit sync cache commands at module removal]

linux-scsi-reference: <[email protected]>

---
 drivers/scsi/libsas/sas_ata.c       |    4 ++++
 drivers/scsi/libsas/sas_expander.c  |    3 +++
 drivers/scsi/libsas/sas_scsi_host.c |    7 +++++++
 include/scsi/libsas.h               |    1 +
 4 files changed, 15 insertions(+), 0 deletions(-)

index 042153c..da2e740 100644
@@ -162,6 +162,10 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
 	unsigned int xfer = 0;
 	unsigned int si;
 
+	/* If the device fell off, no sense in issuing commands */
+	if (dev->gone)
+		return AC_ERR_SYSTEM;
+
 	task = sas_alloc_task(GFP_ATOMIC);
 	if (!task)
 		return AC_ERR_SYSTEM;

index 83dd507..61d81f8 100644
@@ -1724,6 +1724,7 @@ static void sas_unregister_ex_tree(struct domain_device *dev)
 	struct domain_device *child, *n;
 
 	list_for_each_entry_safe(child, n, &ex->children, siblings) {
+		child->gone = 1;
 		if (child->dev_type == EDGE_DEV ||
 		    child->dev_type == FANOUT_DEV)
 			sas_unregister_ex_tree(child);

@@ -1744,6 +1745,7 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent,
 			&ex_dev->children, siblings) {
 			if (SAS_ADDR(child->sas_addr) ==
 			    SAS_ADDR(phy->attached_sas_addr)) {
+				child->gone = 1;
 				if (child->dev_type == EDGE_DEV ||
 				    child->dev_type == FANOUT_DEV)
 					sas_unregister_ex_tree(child);

@@ -1752,6 +1754,7 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent,
 				break;
 			}
 		}
+		parent->gone = 1;
 		sas_disable_routing(parent, phy->attached_sas_addr);
 	}
 	memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);

index f0cfba9..1787bd2 100644
@@ -228,6 +228,13 @@ int sas_queuecommand(struct scsi_cmnd *cmd,
 			goto out;
 		}
 
+		/* If the device fell off, no sense in issuing commands */
+		if (dev->gone) {
+			cmd->result = DID_BAD_TARGET << 16;
+			scsi_done(cmd);
+			goto out;
+		}
+
 		res = -ENOMEM;
 		task = sas_create_task(cmd, dev, GFP_ATOMIC);
 		if (!task)

index d06e13b..3dec194 100644
@@ -205,6 +205,7 @@ struct domain_device {
         };
 
         void *lldd_dev;
+	int gone;
 };
 
 struct sas_discovery_event {

[PATCH] libsas: Don't issue commands to devices that have beenhot-removed

From: Darrick J. Wong <[email protected]>

sd will get hung up issuing commands to flush write cache if a SAS device behind the expander is unplugged without warning. Change libsas to reject commands to domain devices that have already gone away.

[[email protected]: removed setting ->gone in sas_deform_port() to
permit sync cache commands at module removal]

linux-scsi-reference: <[email protected]>

---
 drivers/scsi/libsas/sas_ata.c       |    4 ++++
 drivers/scsi/libsas/sas_expander.c  |    3 +++
 drivers/scsi/libsas/sas_scsi_host.c |    7 +++++++
 include/scsi/libsas.h               |    1 +
 4 files changed, 15 insertions(+), 0 deletions(-)

index 042153c..da2e740 100644
@@ -162,6 +162,10 @@ static unsigned int sas_ata_qc_issue(struct

ata_queued_cmd *qc)
unsigned int xfer = 0;
unsigned int si;

+ /* If the device fell off, no sense in issuing commands */
+ if (dev->gone)
+ return AC_ERR_SYSTEM;
+
task = sas_alloc_task(GFP_ATOMIC);
if (!task)
return AC_ERR_SYSTEM;

b/drivers/scsi/libsas/sas_expander.c
index 83dd507..61d81f8 100644

@@ -1724,6 +1724,7 @@ static void sas_unregister_ex_tree(struct

domain_device *dev)
struct domain_device *child, *n;

list_for_each_entry_safe(child, n, &ex->children, siblings) {
+ child->gone = 1;
if (child->dev_type == EDGE_DEV ||
child->dev_type == FANOUT_DEV)
sas_unregister_ex_tree(child);
@@ -1744,6 +1745,7 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent,
&ex_dev->children, siblings) {
if (SAS_ADDR(child->sas_addr) ==
SAS_ADDR(phy->attached_sas_addr)) {
+ child->gone = 1;
if (child->dev_type == EDGE_DEV ||
child->dev_type == FANOUT_DEV)
sas_unregister_ex_tree(child);
@@ -1752,6 +1754,7 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent,
break;
}
}
+ parent->gone = 1;
sas_disable_routing(parent, phy->attached_sas_addr);
}
memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);

b/drivers/scsi/libsas/sas_scsi_host.c
index f0cfba9..1787bd2 100644

@@ -228,6 +228,13 @@ int sas_queuecommand(struct scsi_cmnd *cmd,
 			goto out;
 		}
 
+		/* If the device fell off, no sense in issuing commands */
+		if (dev->gone) {
+			cmd->result = DID_BAD_TARGET << 16;
+			scsi_done(cmd);
+			goto out;
+		}
+
 		res = -ENOMEM;
 		task = sas_create_task(cmd, dev, GFP_ATOMIC);
 		if (!task)

index d06e13b..3dec194 100644
@@ -205,6 +205,7 @@ struct domain_device {
         };
 
         void *lldd_dev;
+	int gone;
 };
 

[Jack]This one looks good to me! Thanks