[PATCH 5/5] of: Refactor node and property manipulation function locking

From: Rob Herring
Date: Tue Aug 01 2023 - 17:55:47 EST


All callers of __of_{add,remove,update}_property() and
__of_{attach,detach}_node() wrap the call with the devtree_lock
spinlock. Let's move the spinlock into the functions. This allows moving
the sysfs update functions into those functions as well.

Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
drivers/of/base.c | 69 ++++++++++++++++++++++++++--------------------------
drivers/of/dynamic.c | 51 ++++++++++++--------------------------
2 files changed, 50 insertions(+), 70 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 99c07f3cbf10..4ee050ace11e 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1536,8 +1536,12 @@ EXPORT_SYMBOL(of_count_phandle_with_args);
*/
int __of_add_property(struct device_node *np, struct property *prop)
{
+ int rc = 0;
+ unsigned long flags;
struct property **next;

+ raw_spin_lock_irqsave(&devtree_lock, flags);
+
/* If the property is in deadprops then it must be removed */
for (next = &np->deadprops; *next; next = &(*next)->next) {
if (*next == prop) {
@@ -1549,15 +1553,21 @@ int __of_add_property(struct device_node *np, struct property *prop)
prop->next = NULL;
next = &np->properties;
while (*next) {
- if (strcmp(prop->name, (*next)->name) == 0)
+ if (strcmp(prop->name, (*next)->name) == 0) {
/* duplicate ! don't insert it */
- return -EEXIST;
-
+ rc = -EEXIST;
+ goto out;
+ }
next = &(*next)->next;
}
*next = prop;

- return 0;
+out:
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+ if (!rc)
+ __of_add_property_sysfs(np, prop);
+
+ return rc;
}

/**
@@ -1567,23 +1577,12 @@ int __of_add_property(struct device_node *np, struct property *prop)
*/
int of_add_property(struct device_node *np, struct property *prop)
{
- unsigned long flags;
int rc;

mutex_lock(&of_mutex);
-
- raw_spin_lock_irqsave(&devtree_lock, flags);
rc = __of_add_property(np, prop);
- raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
- if (!rc)
- __of_add_property_sysfs(np, prop);
-
mutex_unlock(&of_mutex);

- if (!rc)
- of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
-
return rc;
}
EXPORT_SYMBOL_GPL(of_add_property);
@@ -1591,20 +1590,29 @@ EXPORT_SYMBOL_GPL(of_add_property);
int __of_remove_property(struct device_node *np, struct property *prop)
{
struct property **next;
+ unsigned long flags;
+ int rc = 0;
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);

for (next = &np->properties; *next; next = &(*next)->next) {
if (*next == prop)
break;
}
- if (*next == NULL)
- return -ENODEV;
-
+ if (*next == NULL) {
+ rc = -ENODEV;
+ goto out;
+ }
/* found the node */
*next = prop->next;
prop->next = np->deadprops;
np->deadprops = prop;

- return 0;
+out:
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+ if (!rc)
+ __of_remove_property_sysfs(np, prop);
+ return rc;
}

/**
@@ -1619,21 +1627,13 @@ int __of_remove_property(struct device_node *np, struct property *prop)
*/
int of_remove_property(struct device_node *np, struct property *prop)
{
- unsigned long flags;
int rc;

if (!prop)
return -ENODEV;

mutex_lock(&of_mutex);
-
- raw_spin_lock_irqsave(&devtree_lock, flags);
rc = __of_remove_property(np, prop);
- raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
- if (!rc)
- __of_remove_property_sysfs(np, prop);
-
mutex_unlock(&of_mutex);

if (!rc)
@@ -1647,6 +1647,9 @@ int __of_update_property(struct device_node *np, struct property *newprop,
struct property **oldpropp)
{
struct property **next, *oldprop;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);

/* If the property is in deadprops then it must be removed */
for (next = &np->deadprops; *next; next = &(*next)->next) {
@@ -1675,6 +1678,10 @@ int __of_update_property(struct device_node *np, struct property *newprop,
*next = newprop;
}

+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ __of_update_property_sysfs(np, newprop, oldprop);
+
return 0;
}

@@ -1690,21 +1697,13 @@ int __of_update_property(struct device_node *np, struct property *newprop,
int of_update_property(struct device_node *np, struct property *newprop)
{
struct property *oldprop;
- unsigned long flags;
int rc;

if (!newprop->name)
return -EINVAL;

mutex_lock(&of_mutex);
-
- raw_spin_lock_irqsave(&devtree_lock, flags);
rc = __of_update_property(np, newprop, &oldprop);
- raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
- if (!rc)
- __of_update_property_sysfs(np, newprop, oldprop);
-
mutex_unlock(&of_mutex);

if (!rc)
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 4fd3699691b6..c59f581792f1 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -199,6 +199,9 @@ static void __of_attach_node(struct device_node *np)
{
const __be32 *phandle;
int sz;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);

if (!of_node_check_flag(np, OF_OVERLAY)) {
np->name = __of_get_property(np, "name", NULL);
@@ -221,6 +224,10 @@ static void __of_attach_node(struct device_node *np)
np->parent->child = np;
of_node_clear_flag(np, OF_DETACHED);
np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE;
+
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ __of_attach_node_sysfs(np);
}

/**
@@ -230,17 +237,12 @@ static void __of_attach_node(struct device_node *np)
int of_attach_node(struct device_node *np)
{
struct of_reconfig_data rd;
- unsigned long flags;

memset(&rd, 0, sizeof(rd));
rd.dn = np;

mutex_lock(&of_mutex);
- raw_spin_lock_irqsave(&devtree_lock, flags);
__of_attach_node(np);
- raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
- __of_attach_node_sysfs(np);
mutex_unlock(&of_mutex);

of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
@@ -251,13 +253,15 @@ int of_attach_node(struct device_node *np)
void __of_detach_node(struct device_node *np)
{
struct device_node *parent;
+ unsigned long flags;

- if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
- return;
+ raw_spin_lock_irqsave(&devtree_lock, flags);

parent = np->parent;
- if (WARN_ON(!parent))
+ if (WARN_ON(of_node_check_flag(np, OF_DETACHED) || !parent)) {
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
return;
+ }

if (parent->child == np)
parent->child = np->sibling;
@@ -274,6 +278,10 @@ void __of_detach_node(struct device_node *np)

/* race with of_find_node_by_phandle() prevented by devtree_lock */
__of_phandle_cache_inv_entry(np->phandle);
+
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ __of_detach_node_sysfs(np);
}

/**
@@ -283,17 +291,12 @@ void __of_detach_node(struct device_node *np)
int of_detach_node(struct device_node *np)
{
struct of_reconfig_data rd;
- unsigned long flags;

memset(&rd, 0, sizeof(rd));
rd.dn = np;

mutex_lock(&of_mutex);
- raw_spin_lock_irqsave(&devtree_lock, flags);
__of_detach_node(np);
- raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
- __of_detach_node_sysfs(np);
mutex_unlock(&of_mutex);

of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
@@ -565,13 +568,11 @@ static int __of_changeset_entry_notify(struct of_changeset_entry *ce,

static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
{
- unsigned long flags;
int ret = 0;

if (pr_debug("changeset: applying: cset<%p> ", ce))
of_changeset_action_print(ce->action, ce->np, ce->prop ? ce->prop->name : NULL);

- raw_spin_lock_irqsave(&devtree_lock, flags);
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
__of_attach_node(ce->np);
@@ -592,7 +593,6 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
default:
ret = -EINVAL;
}
- raw_spin_unlock_irqrestore(&devtree_lock, flags);

if (ret) {
pr_err("changeset: apply failed: cset<%p> ", ce);
@@ -600,25 +600,6 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
return ret;
}

- switch (ce->action) {
- case OF_RECONFIG_ATTACH_NODE:
- __of_attach_node_sysfs(ce->np);
- break;
- case OF_RECONFIG_DETACH_NODE:
- __of_detach_node_sysfs(ce->np);
- break;
- case OF_RECONFIG_ADD_PROPERTY:
- /* ignore duplicate names */
- __of_add_property_sysfs(ce->np, ce->prop);
- break;
- case OF_RECONFIG_REMOVE_PROPERTY:
- __of_remove_property_sysfs(ce->np, ce->prop);
- break;
- case OF_RECONFIG_UPDATE_PROPERTY:
- __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
- break;
- }
-
return 0;
}


--
2.40.1