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android_kernel_xiaomi_sm7250/drivers/base/base.h
Saravana Kannan 301a95087d UPSTREAM: driver core: Don't do deferred probe in parallel with kernel_init thread 
The current deferred probe implementation can mess up suspend/resume
ordering if deferred probe thread is kicked off in parallel with the
main initcall thread (kernel_init thread) [1].

For example:

Say device-B is a consumer of device-A.

Initcall thread					Deferred probe thread
===============					=====================
1. device-A is added.
2. device-B is added.
3. dpm_list is now [device-A, device-B].
4. driver-A defers probe of device-A.
						5. device-A is moved to
						   end of dpm_list
						6. dpm_list is now
						   [device-B, device-A]
7. driver-B is registereed and probes device-B.
8. dpm_list stays as [device-B, device-A].

The reverse order of dpm_list is used for suspend. So in this case
device-A would incorrectly get suspended before device-B.

Commit 716a7a259690 ("driver core: fw_devlink: Add support for batching
fwnode parsing") kicked off the deferred probe thread early during boot
to run in parallel with the initcall thread and caused suspend/resume
regressions.  This patch removes the parallel run of the deferred probe
thread to avoid the suspend/resume regressions.

[1] - https://lore.kernel.org/lkml/CAGETcx8W96KAw-d_siTX4qHB_-7ddk0miYRDQeHE6E0_8qx-6Q@mail.gmail.com/

Fixes: 716a7a259690 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit cec72f3efc6272420c2c2c699607f03d09b93e41)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ib4c56f6100d4d39f187b75d9e6680b6fb3dfbe52
2020-11-15 15:06:10 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/notifier.h>
/**
* struct subsys_private - structure to hold the private to the driver core portions of the bus_type/class structure.
*
* @subsys - the struct kset that defines this subsystem
* @devices_kset - the subsystem's 'devices' directory
* @interfaces - list of subsystem interfaces associated
* @mutex - protect the devices, and interfaces lists.
*
* @drivers_kset - the list of drivers associated
* @klist_devices - the klist to iterate over the @devices_kset
* @klist_drivers - the klist to iterate over the @drivers_kset
* @bus_notifier - the bus notifier list for anything that cares about things
* on this bus.
* @bus - pointer back to the struct bus_type that this structure is associated
* with.
*
* @glue_dirs - "glue" directory to put in-between the parent device to
* avoid namespace conflicts
* @class - pointer back to the struct class that this structure is associated
* with.
*
* This structure is the one that is the actual kobject allowing struct
* bus_type/class to be statically allocated safely. Nothing outside of the
* driver core should ever touch these fields.
*/
struct subsys_private {
struct kset subsys;
struct kset *devices_kset;
struct list_head interfaces;
struct mutex mutex;
struct kset *drivers_kset;
struct klist klist_devices;
struct klist klist_drivers;
struct blocking_notifier_head bus_notifier;
unsigned int drivers_autoprobe:1;
struct bus_type *bus;
struct kset glue_dirs;
struct class *class;
};
#define to_subsys_private(obj) container_of(obj, struct subsys_private, subsys.kobj)
struct driver_private {
struct kobject kobj;
struct klist klist_devices;
struct klist_node knode_bus;
struct module_kobject *mkobj;
struct device_driver *driver;
};
#define to_driver(obj) container_of(obj, struct driver_private, kobj)
/**
* struct device_private - structure to hold the private to the driver core portions of the device structure.
*
* @klist_children - klist containing all children of this device
* @knode_parent - node in sibling list
* @knode_driver - node in driver list
* @knode_bus - node in bus list
* @deferred_probe - entry in deferred_probe_list which is used to retry the
* binding of drivers which were unable to get all the resources needed by
* the device; typically because it depends on another driver getting
* probed first.
* @device - pointer back to the struct device that this structure is
* associated with.
* @dead - This device is currently either in the process of or has been
* removed from the system. Any asynchronous events scheduled for this
* device should exit without taking any action.
*
* Nothing outside of the driver core should ever touch these fields.
*/
struct device_private {
struct klist klist_children;
struct klist_node knode_parent;
struct klist_node knode_driver;
struct klist_node knode_bus;
struct list_head deferred_probe;
struct device *device;
u8 dead:1;
};
#define to_device_private_parent(obj) \
container_of(obj, struct device_private, knode_parent)
#define to_device_private_driver(obj) \
container_of(obj, struct device_private, knode_driver)
#define to_device_private_bus(obj) \
container_of(obj, struct device_private, knode_bus)
/* initialisation functions */
extern int devices_init(void);
extern int buses_init(void);
extern int classes_init(void);
extern int firmware_init(void);
#ifdef CONFIG_SYS_HYPERVISOR
extern int hypervisor_init(void);
#else
static inline int hypervisor_init(void) { return 0; }
#endif
extern int platform_bus_init(void);
extern void cpu_dev_init(void);
extern void container_dev_init(void);
struct kobject *virtual_device_parent(struct device *dev);
extern int bus_add_device(struct device *dev);
extern void bus_probe_device(struct device *dev);
extern void bus_remove_device(struct device *dev);
extern int bus_add_driver(struct device_driver *drv);
extern void bus_remove_driver(struct device_driver *drv);
extern void device_release_driver_internal(struct device *dev,
struct device_driver *drv,
struct device *parent);
extern void driver_detach(struct device_driver *drv);
extern int driver_probe_device(struct device_driver *drv, struct device *dev);
extern void driver_deferred_probe_del(struct device *dev);
static inline int driver_match_device(struct device_driver *drv,
struct device *dev)
{
return drv->bus->match ? drv->bus->match(dev, drv) : 1;
}
extern bool driver_allows_async_probing(struct device_driver *drv);
extern int driver_add_groups(struct device_driver *drv,
const struct attribute_group **groups);
extern void driver_remove_groups(struct device_driver *drv,
const struct attribute_group **groups);
extern char *make_class_name(const char *name, struct kobject *kobj);
extern int devres_release_all(struct device *dev);
extern void device_block_probing(void);
extern void device_unblock_probing(void);
/* /sys/devices directory */
extern struct kset *devices_kset;
extern void devices_kset_move_last(struct device *dev);
#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);
#else
static inline void module_add_driver(struct module *mod,
struct device_driver *drv) { }
static inline void module_remove_driver(struct device_driver *drv) { }
#endif
#ifdef CONFIG_DEVTMPFS
extern int devtmpfs_init(void);
#else
static inline int devtmpfs_init(void) { return 0; }
#endif
/* Device links support */
extern int device_links_read_lock(void);
extern void device_links_read_unlock(int idx);
extern int device_links_check_suppliers(struct device *dev);
extern void device_links_driver_bound(struct device *dev);
extern void device_links_driver_cleanup(struct device *dev);
extern void device_links_no_driver(struct device *dev);
extern bool device_links_busy(struct device *dev);
extern void device_links_unbind_consumers(struct device *dev);
/* device pm support */
void device_pm_move_to_tail(struct device *dev);
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