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driver core: Add deferred_probe attribute to devices in sysfs

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It is sometimes useful to know that a device is on the deferred probe
list rather than, say, not having a driver available.  Expose this
information to user-space.

Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ben Hutchings
2016-08-16 14:34:18 +01:00
committed by Greg Kroah-Hartman
parent baa8809f60
commit 6751667a29
4 changed files with 34 additions and 0 deletions
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2
drivers/base/base.h
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@@ -141,6 +141,8 @@ extern void device_unblock_probing(void);
extern struct kset *devices_kset;
extern void devices_kset_move_last(struct device *dev);
extern struct device_attribute dev_attr_deferred_probe;
#if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
extern void module_add_driver(struct module *mod, struct device_driver *drv);
extern void module_remove_driver(struct device_driver *drv);

7
drivers/base/core.c
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@@ -1060,8 +1060,14 @@ static int device_add_attrs(struct device *dev)
goto err_remove_dev_groups;
}
error = device_create_file(dev, &dev_attr_deferred_probe);
if (error)
goto err_remove_online;
return 0;
err_remove_online:
device_remove_file(dev, &dev_attr_online);
err_remove_dev_groups:
device_remove_groups(dev, dev->groups);
err_remove_type_groups:
@@ -1079,6 +1085,7 @@ static void device_remove_attrs(struct device *dev)
struct class *class = dev->class;
const struct device_type *type = dev->type;
device_remove_file(dev, &dev_attr_deferred_probe);
device_remove_file(dev, &dev_attr_online);
device_remove_groups(dev, dev->groups);

13
drivers/base/dd.c
View File

@@ -53,6 +53,19 @@ static LIST_HEAD(deferred_probe_pending_list);
static LIST_HEAD(deferred_probe_active_list);
static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
static ssize_t deferred_probe_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
bool value;
mutex_lock(&deferred_probe_mutex);
value = !list_empty(&dev->p->deferred_probe);
mutex_unlock(&deferred_probe_mutex);
return sprintf(buf, "%d\n", value);
}
DEVICE_ATTR_RO(deferred_probe);
/*
* In some cases, like suspend to RAM or hibernation, It might be reasonable
* to prohibit probing of devices as it could be unsafe.