[PATCH 18/31] uio: Statically allocate uio_class and use class .dev_attrs.

From: Greg Kroah-Hartman
Date: Fri Oct 22 2010 - 14:28:47 EST


From: Eric W. Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>

Instead of adding uio class attributes manually after the uio device has
been created and we have sent a uevent to userspace, use the class
attribute mechanism. This removes races and makes the code simpler.

At the same time don't bother to dynamically allocate a struct class for
uio, just declare one statically. Less code is needed and it is easier
to set the class parameters.tune the class

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Hans J. Koch <hjk@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/uio/uio.c | 53 ++++++++++++++++++-----------------------------------
1 files changed, 18 insertions(+), 35 deletions(-)

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 3d4d65b..3fe9a9d 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -46,9 +46,6 @@ static struct cdev *uio_cdev;
static DEFINE_IDR(uio_idr);
static const struct file_operations uio_fops;

-/* UIO class infrastructure */
-static struct class *uio_class;
-
/* Protect idr accesses */
static DEFINE_MUTEX(minor_lock);

@@ -233,7 +230,6 @@ static ssize_t show_name(struct device *dev,
struct uio_device *idev = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", idev->info->name);
}
-static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static ssize_t show_version(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -241,7 +237,6 @@ static ssize_t show_version(struct device *dev,
struct uio_device *idev = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", idev->info->version);
}
-static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);

static ssize_t show_event(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -249,17 +244,18 @@ static ssize_t show_event(struct device *dev,
struct uio_device *idev = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
}
-static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);

-static struct attribute *uio_attrs[] = {
- &dev_attr_name.attr,
- &dev_attr_version.attr,
- &dev_attr_event.attr,
- NULL,
+static struct device_attribute uio_class_attributes[] = {
+ __ATTR(name, S_IRUGO, show_name, NULL),
+ __ATTR(version, S_IRUGO, show_version, NULL),
+ __ATTR(event, S_IRUGO, show_event, NULL),
+ {}
};

-static struct attribute_group uio_attr_grp = {
- .attrs = uio_attrs,
+/* UIO class infrastructure */
+static struct class uio_class = {
+ .name = "uio",
+ .dev_attrs = uio_class_attributes,
};

/*
@@ -276,10 +272,6 @@ static int uio_dev_add_attributes(struct uio_device *idev)
struct uio_port *port;
struct uio_portio *portio;

- ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
- if (ret)
- goto err_group;
-
for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
mem = &idev->info->mem[mi];
if (mem->size == 0)
@@ -347,8 +339,6 @@ err_map:
kobject_put(&map->kobj);
}
kobject_put(idev->map_dir);
- sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
-err_group:
dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
return ret;
}
@@ -374,8 +364,6 @@ static void uio_dev_del_attributes(struct uio_device *idev)
kobject_put(&port->portio->kobj);
}
kobject_put(idev->portio_dir);
-
- sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
}

static int uio_get_minor(struct uio_device *idev)
@@ -775,7 +763,6 @@ static void uio_major_cleanup(void)

static int init_uio_class(void)
{
- struct class *class;
int ret;

/* This is the first time in here, set everything up properly */
@@ -783,16 +770,14 @@ static int init_uio_class(void)
if (ret)
goto exit;

- class = class_create(THIS_MODULE, "uio");
- if (IS_ERR(class)) {
- ret = IS_ERR(class);
- printk(KERN_ERR "class_create failed for uio\n");
- goto err_class_create;
+ ret = class_register(&uio_class);
+ if (ret) {
+ printk(KERN_ERR "class_register failed for uio\n");
+ goto err_class_register;
}
- uio_class = class;
return 0;

-err_class_create:
+err_class_register:
uio_major_cleanup();
exit:
return ret;
@@ -800,9 +785,7 @@ exit:

static void release_uio_class(void)
{
- /* Ok, we cheat as we know we only have one uio_class */
- class_destroy(uio_class);
- uio_class = NULL;
+ class_unregister(&uio_class);
uio_major_cleanup();
}

@@ -841,7 +824,7 @@ int __uio_register_device(struct module *owner,
if (ret)
goto err_get_minor;

- idev->dev = device_create(uio_class, parent,
+ idev->dev = device_create(&uio_class, parent,
MKDEV(uio_major, idev->minor), idev,
"uio%d", idev->minor);
if (IS_ERR(idev->dev)) {
@@ -868,7 +851,7 @@ int __uio_register_device(struct module *owner,
err_request_irq:
uio_dev_del_attributes(idev);
err_uio_dev_add_attributes:
- device_destroy(uio_class, MKDEV(uio_major, idev->minor));
+ device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
err_device_create:
uio_free_minor(idev);
err_get_minor:
@@ -899,7 +882,7 @@ void uio_unregister_device(struct uio_info *info)

uio_dev_del_attributes(idev);

- device_destroy(uio_class, MKDEV(uio_major, idev->minor));
+ device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
kfree(idev);

return;
--
1.7.2

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