From c31a0c052205e3ec24efc3fe18ef70c3e913f2d4 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Mon, 11 Feb 2013 14:15:32 -0700 Subject: of: fix recursive locking in of_get_next_available_child() 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 Signed-off-by: Grant Likely --- drivers/of/base.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) (limited to 'drivers/of') diff --git a/drivers/of/base.c b/drivers/of/base.c index e8d65aff8639..f7a87ce1b480 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -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; -- cgit v1.2.3-59-g8ed1b