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Message-ID: <20150811063549.GB5147@linux>
Date: Tue, 11 Aug 2015 12:05:49 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Stephen Boyd <sboyd@...eaurora.org>
Cc: Rafael Wysocki <rjw@...ysocki.net>, nm@...com,
linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
khilman@...aro.org,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Dmitry Torokhov <dtor@...omium.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Len Brown <len.brown@...el.com>,
open list <linux-kernel@...r.kernel.org>,
Pavel Machek <pavel@....cz>
Subject: Re: [PATCH 6/6] PM / OPP: Add debugfs support
On 10-08-15, 12:50, Stephen Boyd wrote:
> > + /* Create device specific directory link */
> > + d = debugfs_create_symlink(dev_name(dev), rootdir,
>
> The dev_name thing is going to fail. Eventually we'll get into a
> situation where two devices with the same name on different
> busses have OPPs. When we add them to debugfs their names are
> going to conflict. The regulator core suffered this problem, see
> commit a9eaa8130707 (regulator: Ensure unique regulator debugfs
> directory names, 2014-10-17) for one solution.
The regulator core had a slightly different problem probably as it was
assigning similar names to devices of same type. And we may not hit
it.
But still, I have prefixed it with parent name to make it look
slightly stronger :)
Diff with earlier patch (only compile tested for now, don't have
access to setup currently):
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index b3af1825266a..871502dec381 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -679,7 +679,7 @@ static int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
new_opp->dev_opp = dev_opp;
list_add_rcu(&new_opp->node, head);
- ret = opp_debug_create_one(new_opp, dev_opp->dentry);
+ ret = opp_debug_create_one(new_opp, dev_opp);
if (ret)
dev_err(dev, "%s: Failed to register opp to debugfs (%d)\n",
__func__, ret);
diff --git a/drivers/base/power/opp/debugfs.c b/drivers/base/power/opp/debugfs.c
index d4e18eac8278..6c048bfbf954 100644
--- a/drivers/base/power/opp/debugfs.c
+++ b/drivers/base/power/opp/debugfs.c
@@ -17,13 +17,24 @@
static struct dentry *rootdir;
+static void opp_set_dev_name(const struct device *dev, char *name)
+{
+
+ if (dev->parent)
+ snprintf(name, NAME_MAX, "%s-%s", dev_name(dev->parent),
+ dev_name(dev));
+ else
+ snprintf(name, NAME_MAX, "%s", dev_name(dev));
+}
+
void opp_debug_remove_one(struct dev_pm_opp *opp)
{
debugfs_remove_recursive(opp->dentry);
}
-int opp_debug_create_one(struct dev_pm_opp *opp, struct dentry *pdentry)
+int opp_debug_create_one(struct dev_pm_opp *opp, struct device_opp *dev_opp)
{
+ struct dentry *pdentry = dev_opp->dentry;
struct dentry *d;
char name[15];
@@ -75,10 +86,12 @@ static int device_opp_debug_create_dir(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
{
const struct device *dev = list_dev->dev;
- struct dentry *d = NULL;
+ struct dentry *d;
+
+ opp_set_dev_name(dev, dev_opp->dentry_name);
/* Create device specific directory */
- d = debugfs_create_dir(dev_name(dev), rootdir);
+ d = debugfs_create_dir(dev_opp->dentry_name, rootdir);
if (!d) {
dev_err(dev, "%s: Failed to create debugfs dir\n", __func__);
return -ENOMEM;
@@ -86,7 +99,6 @@ static int device_opp_debug_create_dir(struct device_list_opp *list_dev,
list_dev->dentry = d;
dev_opp->dentry = d;
- dev_opp->debugfs_dev = dev;
return 0;
}
@@ -95,11 +107,13 @@ static int device_opp_debug_create_link(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
{
const struct device *dev = list_dev->dev;
- struct dentry *d = NULL;
+ char name[NAME_MAX];
+ struct dentry *d;
+
+ opp_set_dev_name(list_dev->dev, name);
/* Create device specific directory link */
- d = debugfs_create_symlink(dev_name(dev), rootdir,
- dev_name(dev_opp->debugfs_dev));
+ d = debugfs_create_symlink(name, rootdir, dev_opp->dentry_name);
if (!d) {
dev_err(dev, "%s: Failed to create link\n", __func__);
return -ENOMEM;
@@ -135,6 +149,36 @@ int opp_debug_register(struct device_list_opp *list_dev,
return device_opp_debug_create_dir(list_dev, dev_opp);
}
+static void opp_migrate_dentry(struct device_list_opp *list_dev,
+ struct device_opp *dev_opp)
+{
+ struct device_list_opp *new_dev;
+ const struct device *dev;
+ struct dentry *dentry;
+
+ /* Look for next list-dev */
+ list_for_each_entry(new_dev, &dev_opp->dev_list, node)
+ if (new_dev != list_dev)
+ break;
+
+ /* new_dev is guaranteed to be valid here */
+ dev = new_dev->dev;
+ debugfs_remove_recursive(new_dev->dentry);
+
+ opp_set_dev_name(dev, dev_opp->dentry_name);
+
+ dentry = debugfs_rename(rootdir, list_dev->dentry, rootdir,
+ dev_opp->dentry_name);
+ if (!dentry) {
+ dev_err(dev, "%s: Failed to rename link from: %s to %s\n",
+ __func__, dev_name(list_dev->dev), dev_name(dev));
+ return;
+ }
+
+ new_dev->dentry = dentry;
+ dev_opp->dentry = dentry;
+}
+
/**
* opp_debug_unregister - remove a device opp node from debugfs opp directory
* @list_dev: list-dev pointer for device
@@ -145,9 +189,18 @@ int opp_debug_register(struct device_list_opp *list_dev,
void opp_debug_unregister(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
{
- debugfs_remove_recursive(list_dev->dentry);
- if (list_dev->dentry == dev_opp->dentry)
+ if (list_dev->dentry == dev_opp->dentry) {
+ /* Move the real dentry object under another device */
+ if (!list_is_singular(&dev_opp->dev_list)) {
+ opp_migrate_dentry(list_dev, dev_opp);
+ goto out;
+ }
dev_opp->dentry = NULL;
+ }
+
+ debugfs_remove_recursive(list_dev->dentry);
+
+out:
list_dev->dentry = NULL;
}
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 8eb6a9a098a1..0e4c27fb0c4a 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -17,6 +17,7 @@
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/list.h>
+#include <linux/limits.h>
#include <linux/pm_opp.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
@@ -83,8 +84,10 @@ struct dev_pm_opp {
struct device_node *np;
+#ifdef CONFIG_DEBUG_FS
/* debugfs */
struct dentry *dentry;
+#endif
};
/**
@@ -102,8 +105,10 @@ struct device_list_opp {
const struct device *dev;
struct rcu_head rcu_head;
+#ifdef CONFIG_DEBUG_FS
/* debugfs */
struct dentry *dentry;
+#endif
};
/**
@@ -120,7 +125,7 @@ struct device_list_opp {
* @np: struct device_node pointer for opp's DT node.
* @shared_opp: OPP is shared between multiple devices.
* @dentry: debugfs dentry pointer of the real device directory (not links).
- * @debugfs_dev: Pointer to device for which the real directory was created.
+ * @dentry_name: Name of the real dentry.
*
* This is an internal data structure maintaining the link to opps attached to
* a device. This structure is not meant to be shared to users as it is
@@ -143,9 +148,11 @@ struct device_opp {
bool shared_opp;
struct dev_pm_opp *suspend_opp;
+#ifdef CONFIG_DEBUG_FS
/* debugfs */
struct dentry *dentry;
- const struct device *debugfs_dev;
+ char dentry_name[NAME_MAX];
+#endif
};
/* Routines internal to opp core */
@@ -156,7 +163,7 @@ struct device_node *_of_get_opp_desc_node(struct device *dev);
#ifdef CONFIG_DEBUG_FS
void opp_debug_remove_one(struct dev_pm_opp *opp);
-int opp_debug_create_one(struct dev_pm_opp *opp, struct dentry *pdentry);
+int opp_debug_create_one(struct dev_pm_opp *opp, struct device_opp *dev_opp);
int opp_debug_register(struct device_list_opp *list_dev,
struct device_opp *dev_opp);
void opp_debug_unregister(struct device_list_opp *list_dev,
@@ -165,7 +172,7 @@ void opp_debug_unregister(struct device_list_opp *list_dev,
static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
static inline int opp_debug_create_one(struct dev_pm_opp *opp,
- struct dentry *pdentry)
+ struct device_opp *dev_opp)
{ return 0; }
static inline int opp_debug_register(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
--
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