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[SCSI] libsas: fix domain_device leak
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Arrange for the deallocation of a struct domain_device object when it no
longer has:
1/ any children
2/ references by any scsi_targets
3/ references by a lldd

The comment about domain_device lifetime in
Documentation/scsi/libsas.txt is stale as it appears mainline never had
a version of a struct domain_device that was registered as a kobject.
We now manage domain_device reference counts on behalf of external
agents.

Reviewed-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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Dan Williams authored and James Bottomley committed Feb 19, 2012
1 parent 6f4e75a commit 735f7d2
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Showing 6 changed files with 56 additions and 41 deletions.
15 changes: 0 additions & 15 deletions Documentation/scsi/libsas.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -398,21 +398,6 @@ struct sas_task {
task_done -- callback when the task has finished execution
};

When an external entity, entity other than the LLDD or the
SAS Layer, wants to work with a struct domain_device, it
_must_ call kobject_get() when getting a handle on the
device and kobject_put() when it is done with the device.

This does two things:
A) implements proper kfree() for the device;
B) increments/decrements the kref for all players:
domain_device
all domain_device's ... (if past an expander)
port
host adapter
pci device
and up the ladder, etc.

DISCOVERY
---------

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36 changes: 24 additions & 12 deletions drivers/scsi/libsas/sas_discover.c
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Original file line number Diff line number Diff line change
Expand Up @@ -36,8 +36,6 @@

void sas_init_dev(struct domain_device *dev)
{
INIT_LIST_HEAD(&dev->siblings);
INIT_LIST_HEAD(&dev->dev_list_node);
switch (dev->dev_type) {
case SAS_END_DEV:
break;
Expand Down Expand Up @@ -73,14 +71,14 @@ static int sas_get_port_device(struct asd_sas_port *port)
struct sas_rphy *rphy;
struct domain_device *dev;

dev = kzalloc(sizeof(*dev), GFP_KERNEL);
dev = sas_alloc_device();
if (!dev)
return -ENOMEM;

spin_lock_irqsave(&port->phy_list_lock, flags);
if (list_empty(&port->phy_list)) {
spin_unlock_irqrestore(&port->phy_list_lock, flags);
kfree(dev);
sas_put_device(dev);
return -ENODEV;
}
phy = container_of(port->phy_list.next, struct asd_sas_phy, port_phy_el);
Expand Down Expand Up @@ -130,7 +128,7 @@ static int sas_get_port_device(struct asd_sas_port *port)
}

if (!rphy) {
kfree(dev);
sas_put_device(dev);
return -ENODEV;
}
rphy->identify.phy_identifier = phy->phy->identify.phy_identifier;
Expand Down Expand Up @@ -173,6 +171,7 @@ int sas_notify_lldd_dev_found(struct domain_device *dev)
dev_name(sas_ha->dev),
SAS_ADDR(dev->sas_addr), res);
}
kref_get(&dev->kref);
}
return res;
}
Expand All @@ -184,8 +183,10 @@ void sas_notify_lldd_dev_gone(struct domain_device *dev)
struct Scsi_Host *shost = sas_ha->core.shost;
struct sas_internal *i = to_sas_internal(shost->transportt);

if (i->dft->lldd_dev_gone)
if (i->dft->lldd_dev_gone) {
i->dft->lldd_dev_gone(dev);
sas_put_device(dev);
}
}

/* ---------- Common/dispatchers ---------- */
Expand Down Expand Up @@ -219,6 +220,20 @@ int sas_discover_end_dev(struct domain_device *dev)

/* ---------- Device registration and unregistration ---------- */

void sas_free_device(struct kref *kref)
{
struct domain_device *dev = container_of(kref, typeof(*dev), kref);

if (dev->parent)
sas_put_device(dev->parent);

/* remove the phys and ports, everything else should be gone */
if (dev->dev_type == EDGE_DEV || dev->dev_type == FANOUT_DEV)
kfree(dev->ex_dev.ex_phy);

kfree(dev);
}

static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_device *dev)
{
sas_notify_lldd_dev_gone(dev);
Expand All @@ -230,6 +245,8 @@ static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_d
spin_lock_irq(&port->dev_list_lock);
list_del_init(&dev->dev_list_node);
spin_unlock_irq(&port->dev_list_lock);

sas_put_device(dev);
}

void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
Expand All @@ -239,11 +256,6 @@ void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
sas_rphy_delete(dev->rphy);
dev->rphy = NULL;
}
if (dev->dev_type == EDGE_DEV || dev->dev_type == FANOUT_DEV) {
/* remove the phys and ports, everything else should be gone */
kfree(dev->ex_dev.ex_phy);
dev->ex_dev.ex_phy = NULL;
}
sas_unregister_common_dev(port, dev);
}

Expand Down Expand Up @@ -322,7 +334,7 @@ static void sas_discover_domain(struct work_struct *work)
list_del_init(&dev->dev_list_node);
spin_unlock_irq(&port->dev_list_lock);

kfree(dev); /* not kobject_register-ed yet */
sas_put_device(dev);
port->port_dev = NULL;
}

Expand Down
10 changes: 6 additions & 4 deletions drivers/scsi/libsas/sas_expander.c
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Original file line number Diff line number Diff line change
Expand Up @@ -657,10 +657,11 @@ static struct domain_device *sas_ex_discover_end_dev(
if (phy->attached_sata_host || phy->attached_sata_ps)
return NULL;

child = kzalloc(sizeof(*child), GFP_KERNEL);
child = sas_alloc_device();
if (!child)
return NULL;

kref_get(&parent->kref);
child->parent = parent;
child->port = parent->port;
child->iproto = phy->attached_iproto;
Expand Down Expand Up @@ -762,7 +763,7 @@ static struct domain_device *sas_ex_discover_end_dev(
sas_port_delete(phy->port);
out_err:
phy->port = NULL;
kfree(child);
sas_put_device(child);
return NULL;
}

Expand Down Expand Up @@ -809,7 +810,7 @@ static struct domain_device *sas_ex_discover_expander(
phy->attached_phy_id);
return NULL;
}
child = kzalloc(sizeof(*child), GFP_KERNEL);
child = sas_alloc_device();
if (!child)
return NULL;

Expand All @@ -835,6 +836,7 @@ static struct domain_device *sas_ex_discover_expander(
child->rphy = rphy;
edev = rphy_to_expander_device(rphy);
child->dev_type = phy->attached_dev_type;
kref_get(&parent->kref);
child->parent = parent;
child->port = port;
child->iproto = phy->attached_iproto;
Expand All @@ -858,7 +860,7 @@ static struct domain_device *sas_ex_discover_expander(
spin_lock_irq(&parent->port->dev_list_lock);
list_del(&child->dev_list_node);
spin_unlock_irq(&parent->port->dev_list_lock);
kfree(child);
sas_put_device(child);
return NULL;
}
list_add_tail(&child->siblings, &parent->ex_dev.children);
Expand Down
19 changes: 19 additions & 0 deletions drivers/scsi/libsas/sas_internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,8 @@ struct domain_device *sas_find_dev_by_rphy(struct sas_rphy *rphy);

void sas_hae_reset(struct work_struct *work);

void sas_free_device(struct kref *kref);

#ifdef CONFIG_SCSI_SAS_HOST_SMP
extern int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
struct request *rsp);
Expand Down Expand Up @@ -161,4 +163,21 @@ static inline void sas_add_parent_port(struct domain_device *dev, int phy_id)
sas_port_add_phy(ex->parent_port, ex_phy->phy);
}

static inline struct domain_device *sas_alloc_device(void)
{
struct domain_device *dev = kzalloc(sizeof(*dev), GFP_KERNEL);

if (dev) {
INIT_LIST_HEAD(&dev->siblings);
INIT_LIST_HEAD(&dev->dev_list_node);
kref_init(&dev->kref);
}
return dev;
}

static inline void sas_put_device(struct domain_device *dev)
{
kref_put(&dev->kref, sas_free_device);
}

#endif /* _SAS_INTERNAL_H_ */
16 changes: 6 additions & 10 deletions drivers/scsi/libsas/sas_scsi_host.c
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Original file line number Diff line number Diff line change
Expand Up @@ -737,16 +737,10 @@ struct domain_device *sas_find_dev_by_rphy(struct sas_rphy *rphy)
return found_dev;
}

static inline struct domain_device *sas_find_target(struct scsi_target *starget)
{
struct sas_rphy *rphy = dev_to_rphy(starget->dev.parent);

return sas_find_dev_by_rphy(rphy);
}

int sas_target_alloc(struct scsi_target *starget)
{
struct domain_device *found_dev = sas_find_target(starget);
struct sas_rphy *rphy = dev_to_rphy(starget->dev.parent);
struct domain_device *found_dev = sas_find_dev_by_rphy(rphy);
int res;

if (!found_dev)
Expand All @@ -758,6 +752,7 @@ int sas_target_alloc(struct scsi_target *starget)
return res;
}

kref_get(&found_dev->kref);
starget->hostdata = found_dev;
return 0;
}
Expand Down Expand Up @@ -1047,15 +1042,16 @@ int sas_slave_alloc(struct scsi_device *scsi_dev)

void sas_target_destroy(struct scsi_target *starget)
{
struct domain_device *found_dev = sas_find_target(starget);
struct domain_device *found_dev = starget->hostdata;

if (!found_dev)
return;

if (dev_is_sata(found_dev))
ata_sas_port_destroy(found_dev->sata_dev.ap);

return;
starget->hostdata = NULL;
sas_put_device(found_dev);
}

static void sas_parse_addr(u8 *sas_addr, const char *p)
Expand Down
1 change: 1 addition & 0 deletions include/scsi/libsas.h
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Original file line number Diff line number Diff line change
Expand Up @@ -206,6 +206,7 @@ struct domain_device {

void *lldd_dev;
int gone;
struct kref kref;
};

struct sas_discovery_event {
Expand Down

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