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of: fix recursive locking in of_get_next_available_child()

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of_get_next_available_child() acquires devtree_lock, then calls
of_device_is_available() which calls of_get_property() which calls
of_find_property() which tries to re-acquire devtree_lock, thus causing
deadlock.

To avoid this, create a new __of_device_is_available() which calls
__of_get_property() instead, which calls __of_find_property(), which
does not take the lock,. Update of_get_next_available_child() to call
the new __of_device_is_available() since it already owns the lock.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Stephen Warren 2013-02-11 14:15:32 -07:00 committed by Grant Likely
parent bfc4a58986
commit c31a0c0522
1 changed files with 25 additions and 5 deletions
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30
drivers/of/base.c
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@ -290,19 +290,19 @@ int of_machine_is_compatible(const char *compat)
EXPORT_SYMBOL(of_machine_is_compatible);
/**
* of_device_is_available - check if a device is available for use
* __of_device_is_available - check if a device is available for use
*
* @device: Node to check for availability
* @device: Node to check for availability, with locks already held
*
* Returns 1 if the status property is absent or set to "okay" or "ok",
* 0 otherwise
*/
int of_device_is_available(const struct device_node *device)
static int __of_device_is_available(const struct device_node *device)
{
const char *status;
int statlen;
status = of_get_property(device, "status", &statlen);
status = __of_get_property(device, "status", &statlen);
if (status == NULL)
return 1;
@ -313,6 +313,26 @@ int of_device_is_available(const struct device_node *device)
return 0;
}
/**
* of_device_is_available - check if a device is available for use
*
* @device: Node to check for availability
*
* Returns 1 if the status property is absent or set to "okay" or "ok",
* 0 otherwise
*/
int of_device_is_available(const struct device_node *device)
{
unsigned long flags;
int res;
raw_spin_lock_irqsave(&devtree_lock, flags);
res = __of_device_is_available(device);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
return res;
}
EXPORT_SYMBOL(of_device_is_available);
/**
@ -404,7 +424,7 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
raw_spin_lock(&devtree_lock);
next = prev ? prev->sibling : node->child;
for (; next; next = next->sibling) {
if (!of_device_is_available(next))
if (!__of_device_is_available(next))
continue;
if (of_node_get(next))
break;