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[SCSI] libsas: fix port->dev_list locking 

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

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Dan Williams 2011-09-21 22:05:34 -07:00 committed by James Bottomley
parent 29f366e8a9
commit 1a34c06401
3 changed files with 18 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/scsi/libsas/sas_discover.c
View File

@ -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;

15
drivers/scsi/libsas/sas_expander.c
View File

@ -754,7 +754,10 @@ 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:
@ -1739,7 +1742,7 @@ 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;
@ -1748,11 +1751,11 @@ 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,
@ -1769,9 +1772,9 @@ 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;
}
}

2
include/scsi/libsas.h
View File

@ -656,7 +656,7 @@ 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 *);