linux-kernel - [PATCH 5/9] of: add self parameter to of_update

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Message-Id: <20211007000954.30621-6-zev@bewilderbeest.net>
Date:   Wed,  6 Oct 2021 17:09:50 -0700
From:   Zev Weiss <zev@...ilderbeest.net>
To:     openbmc@...ts.ozlabs.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jeremy Kerr <jk@...econstruct.com.au>,
        Joel Stanley <joel@....id.au>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        Zev Weiss <zev@...ilderbeest.net>,
        Frank Rowand <frowand.list@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 5/9] of: add self parameter to of_update_property()

This is to indicate that the property is being updated via its own
sysfs method so that we ultimately call into kernfs_remove_self() and
avoid the deadlock that would occur otherwise.

Signed-off-by: Zev Weiss <zev@...ilderbeest.net>
---
 drivers/of/base.c       | 7 ++++---
 drivers/of/dynamic.c    | 2 +-
 drivers/of/kobj.c       | 4 ++--
 drivers/of/of_private.h | 4 ++--
 include/linux/of.h      | 7 ++++++-
 5 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index f720c0d246f2..ce4d3bc2f8a6 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1902,8 +1902,9 @@ int __of_update_property(struct device_node *np, struct property *newprop,
 	return 0;
 }
 
+
 /*
- * of_update_property - Update a property in a node, if the property does
+ * of_update_property_self - Update a property in a node, if the property does
  * not exist, add it.
  *
  * Note that we don't actually remove it, since we have given out
@@ -1911,7 +1912,7 @@ int __of_update_property(struct device_node *np, struct property *newprop,
  * Instead we just move the property to the "dead properties" list,
  * and add the new property to the property list
  */
-int of_update_property(struct device_node *np, struct property *newprop)
+int of_update_property_self(struct device_node *np, struct property *newprop, bool self)
 {
 	struct property *oldprop;
 	unsigned long flags;
@@ -1927,7 +1928,7 @@ int of_update_property(struct device_node *np, struct property *newprop)
 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
 	if (!rc)
-		__of_update_property_sysfs(np, newprop, oldprop);
+		__of_update_property_sysfs(np, newprop, oldprop, self);
 
 	mutex_unlock(&of_mutex);
 
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index cd3821a6444f..8a67f3e1b223 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -652,7 +652,7 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 		__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);
+		__of_update_property_sysfs(ce->np, ce->prop, ce->old_prop, false);
 		break;
 	}
 
diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c
index 06d6c90f7aa1..378cb421aae1 100644
--- a/drivers/of/kobj.c
+++ b/drivers/of/kobj.c
@@ -104,14 +104,14 @@ void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
 }
 
 void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
-		struct property *oldprop)
+		struct property *oldprop, bool self)
 {
 	/* At early boot, bail out and defer setup to of_init() */
 	if (!of_kset)
 		return;
 
 	if (oldprop)
-		__of_sysfs_remove_bin_file(np, oldprop, false);
+		__of_sysfs_remove_bin_file(np, oldprop, self);
 	__of_add_property_sysfs(np, newprop);
 }
 
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index fff157c63907..3c6816237278 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -64,7 +64,7 @@ int of_node_is_attached(struct device_node *node);
 int __of_add_property_sysfs(struct device_node *np, struct property *pp);
 void __of_remove_property_sysfs(struct device_node *np, struct property *prop);
 void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
-		struct property *oldprop);
+		struct property *oldprop, bool self);
 int __of_attach_node_sysfs(struct device_node *np);
 void __of_detach_node_sysfs(struct device_node *np);
 #else
@@ -74,7 +74,7 @@ static inline int __of_add_property_sysfs(struct device_node *np, struct propert
 }
 static inline void __of_remove_property_sysfs(struct device_node *np, struct property *prop) {}
 static inline void __of_update_property_sysfs(struct device_node *np,
-		struct property *newprop, struct property *oldprop) {}
+		struct property *newprop, struct property *oldprop, bool self) {}
 static inline int __of_attach_node_sysfs(struct device_node *np)
 {
 	return 0;
diff --git a/include/linux/of.h b/include/linux/of.h
index 6f1c41f109bb..0e6479a884eb 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -401,7 +401,12 @@ extern int of_machine_is_compatible(const char *compat);
 
 extern int of_add_property(struct device_node *np, struct property *prop);
 extern int of_remove_property(struct device_node *np, struct property *prop);
-extern int of_update_property(struct device_node *np, struct property *newprop);
+extern int of_update_property_self(struct device_node *np, struct property *newprop, bool self);
+
+static inline int of_update_property(struct device_node *np, struct property *newprop)
+{
+	return of_update_property_self(np, newprop, false);
+}
 
 /* For updating the device tree at runtime */
 #define OF_RECONFIG_ATTACH_NODE		0x0001
-- 
2.33.0