port->dev_list maintains a list of devices attached to a given sas root port.
It needs to be mutated under a lock as contexts outside of the
single-threaded-libsas-workqueue access the list via sas_find_dev_by_rphy().
Fixup locations where the list was being mutated without a lock.
This is a follow-up to commit 5911e963 "[SCSI] libsas: remove expander
from dev list on error", where Luben noted [1]:
> 2/ We have unlocked list manipulations in sas_ex_discover_end_dev(),
> sas_unregister_common_dev(), and sas_ex_discover_end_dev()
Yes, I can see that and that is very unfortunate.
[1]: http://marc.info/?l=linux-scsi&m=131480962006471&w=2
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Xiangliang Yu <yuxiangl@xxxxxxxxxxx>
Cc: Jack Wang <jack_wang@xxxxxxxxx>
Cc: Mark Salyzyn <msalyzyn@xxxxxxxxxxxxxx>
Cc: Luben Tuikov <ltuikov@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
lockdep does not complain in a simple driver load/unload test on an expander
topology, but want to get wider review / testing before committing.
drivers/scsi/libsas/sas_discover.c | 13 ++++++++-----
drivers/scsi/libsas/sas_expander.c | 15 +++++++++------
include/scsi/libsas.h | 2 +-
3 files changed, 18 insertions(+), 12 deletions(-)
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index f583193..54a5199 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -219,17 +219,20 @@ out_err2:
/* ---------- Device registration and unregistration ---------- */
-static inline void sas_unregister_common_dev(struct domain_device *dev)
+static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_device *dev)
{
sas_notify_lldd_dev_gone(dev);
if (!dev->parent)
dev->port->port_dev = NULL;
else
list_del_init(&dev->siblings);
+
+ spin_lock_irq(&port->dev_list_lock);
list_del_init(&dev->dev_list_node);
+ spin_unlock_irq(&port->dev_list_lock);
}
-void sas_unregister_dev(struct domain_device *dev)
+void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
{
if (dev->rphy) {
sas_remove_children(&dev->rphy->dev);
@@ -241,15 +244,15 @@ void sas_unregister_dev(struct domain_device *dev)
kfree(dev->ex_dev.ex_phy);
dev->ex_dev.ex_phy = NULL;
}
- sas_unregister_common_dev(dev);
+ sas_unregister_common_dev(port, dev);
}
void sas_unregister_domain_devices(struct asd_sas_port *port)
{
struct domain_device *dev, *n;
- list_for_each_entry_safe_reverse(dev,n,&port->dev_list,dev_list_node)
- sas_unregister_dev(dev);
+ list_for_each_entry_safe_reverse(dev, n, &port->dev_list, dev_list_node)
+ sas_unregister_dev(port, dev);
port->port->rphy = NULL;
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 281d01b..969b315 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -752,7 +752,10 @@ static struct domain_device *sas_ex_discover_end_dev(
out_list_del:
sas_rphy_free(child->rphy);
child->rphy = NULL;
+
+ spin_lock_irq(&parent->port->dev_list_lock);
list_del(&child->dev_list_node);
+ spin_unlock_irq(&parent->port->dev_list_lock);
out_free:
sas_port_delete(phy->port);
out_err:
@@ -1737,7 +1740,7 @@ out:
return res;
}
-static void sas_unregister_ex_tree(struct domain_device *dev)
+static void sas_unregister_ex_tree(struct asd_sas_port *port, struct domain_device *dev)
{
struct expander_device *ex = &dev->ex_dev;
struct domain_device *child, *n;
@@ -1746,11 +1749,11 @@ static void sas_unregister_ex_tree(struct domain_device *dev)
child->gone = 1;
if (child->dev_type == EDGE_DEV ||
child->dev_type == FANOUT_DEV)
- sas_unregister_ex_tree(child);
+ sas_unregister_ex_tree(port, child);
else
- sas_unregister_dev(child);
+ sas_unregister_dev(port, child);
}
- sas_unregister_dev(dev);
+ sas_unregister_dev(port, dev);
}
static void sas_unregister_devs_sas_addr(struct domain_device *parent,
@@ -1767,9 +1770,9 @@ static void sas_unregister_devs_sas_addr(struct domain_device *parent,
child->gone = 1;
if (child->dev_type == EDGE_DEV ||
child->dev_type == FANOUT_DEV)
- sas_unregister_ex_tree(child);
+ sas_unregister_ex_tree(parent->port, child);
else
- sas_unregister_dev(child);
+ sas_unregister_dev(parent->port, child);
break;
}
}
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 793f80b..67be7f5 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -655,7 +655,7 @@ int sas_discover_event(struct asd_sas_port *, enum discover_event ev);
int sas_discover_sata(struct domain_device *);
int sas_discover_end_dev(struct domain_device *);
-void sas_unregister_dev(struct domain_device *);
+void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *);
void sas_init_dev(struct domain_device *);
--
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