From: Zhang Ning <[email protected]> deferred probe will be hanlded by deferred_probe_initcall, starts at late_initcall.
this is too late to handle deferred probe, this will block kernel exec to userspace, make kernel initial time longer. if we know when required resources are ready for a list of devices, related deferred drivers can be probe earlier. add these kinds of drivers into logical list, eg, bus_type->deferred_probe_pending_list, then it can be easily handled by bus driver. with analysis above: add manage_deferred to struct bus_type add deferred_probe_pending_list to struct bus_type when manage_deferred is true, deferred probe will be manage by bus. Signed-off-by: Zhang Ning <[email protected]> --- drivers/base/bus.c | 3 ++- drivers/base/dd.c | 24 +++++++++++++++++------- include/linux/device.h | 5 +++++ 3 files changed, 24 insertions(+), 8 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 8bfd27ec73d6..ca8eaf7565db 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -898,7 +898,8 @@ int bus_register(struct bus_type *bus) retval = bus_add_groups(bus, bus->bus_groups); if (retval) goto bus_groups_fail; - + if (bus->manage_deferred) + INIT_LIST_HEAD(&bus->deferred_probe_pending_list); pr_debug("bus: '%s': registered\n", bus->name); return 0; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 1435d7281c66..926e57f8dd2f 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -82,10 +82,8 @@ static void deferred_probe_debug(struct device *dev) dev_name(dev), duration); } -/* - * deferred_probe_work_func() - Retry probing devices in the active list. - */ -static void deferred_probe_work_func(struct work_struct *work) + +void process_deferred_probe(struct list_head *list) { struct device *dev; struct device_private *private; @@ -102,8 +100,8 @@ static void deferred_probe_work_func(struct work_struct *work) * from under our feet. */ mutex_lock(&deferred_probe_mutex); - while (!list_empty(&deferred_probe_active_list)) { - private = list_first_entry(&deferred_probe_active_list, + while (!list_empty(list)) { + private = list_first_entry(list, typeof(*dev->p), deferred_probe); dev = private->device; list_del_init(&private->deferred_probe); @@ -136,6 +134,15 @@ static void deferred_probe_work_func(struct work_struct *work) } mutex_unlock(&deferred_probe_mutex); } + +/* + * deferred_probe_work_func() - Retry probing devices in the active list. + */ +static void deferred_probe_work_func(struct work_struct *work) +{ + process_deferred_probe(&deferred_probe_active_list); +} + static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); static void driver_deferred_probe_add(struct device *dev) @@ -143,7 +150,10 @@ static void driver_deferred_probe_add(struct device *dev) mutex_lock(&deferred_probe_mutex); if (list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Added to deferred list\n"); - list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list); + if (dev->bus->manage_deferred) + list_add_tail(&dev->p->deferred_probe, &dev->bus->deferred_probe_pending_list); + else + list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list); } mutex_unlock(&deferred_probe_mutex); } diff --git a/include/linux/device.h b/include/linux/device.h index 055a69dbcd18..2f70f3124d18 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -143,6 +143,9 @@ struct bus_type { struct lock_class_key lock_key; bool need_parent_lock; + + bool manage_deferred; + struct list_head deferred_probe_pending_list; }; extern int __must_check bus_register(struct bus_type *bus); @@ -151,6 +154,8 @@ extern void bus_unregister(struct bus_type *bus); extern int __must_check bus_rescan_devices(struct bus_type *bus); +extern void process_deferred_probe(struct list_head *list); + /* iterator helpers for buses */ struct subsys_dev_iter { struct klist_iter ki; -- 2.17.1
