Commit 2c3dfba4 authored by Johannes Berg's avatar Johannes Berg
Browse files

rfkill: sync before userspace visibility/changes 



If userspace quickly opens /dev/rfkill after a new
instance was created, it might see the old state of
the instance from before the sync work runs and may
even _change_ the state, only to have the sync work
change it again.

Fix this by doing the sync inline where needed, not
just for /dev/rfkill but also for sysfs.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 6e48ebff

net/rfkill/core.c

+26 −6
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ struct rfkill { 
	bool			persistent;

	bool			polling_paused;

	bool			suspended;

	bool			need_sync;



	const struct rfkill_ops	*ops;

	void			*data;
@@ -368,6 +369,17 @@ static void rfkill_set_block(struct rfkill *rfkill, bool blocked) 
		rfkill_event(rfkill);

}



static void rfkill_sync(struct rfkill *rfkill)

{

	lockdep_assert_held(&rfkill_global_mutex);



	if (!rfkill->need_sync)

		return;



	rfkill_set_block(rfkill, rfkill_global_states[rfkill->type].cur);

	rfkill->need_sync = false;

}



static void rfkill_update_global_state(enum rfkill_type type, bool blocked)

{

	int i;
@@ -730,6 +742,10 @@ static ssize_t soft_show(struct device *dev, struct device_attribute *attr, 
{

	struct rfkill *rfkill = to_rfkill(dev);



	mutex_lock(&rfkill_global_mutex);

	rfkill_sync(rfkill);

	mutex_unlock(&rfkill_global_mutex);



	return sysfs_emit(buf, "%d\n", (rfkill->state & RFKILL_BLOCK_SW) ? 1 : 0);

}
@@ -751,6 +767,7 @@ static ssize_t soft_store(struct device *dev, struct device_attribute *attr, 
		return -EINVAL;



	mutex_lock(&rfkill_global_mutex);

	rfkill_sync(rfkill);

	rfkill_set_block(rfkill, state);

	mutex_unlock(&rfkill_global_mutex);
@@ -783,6 +800,10 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr, 
{

	struct rfkill *rfkill = to_rfkill(dev);



	mutex_lock(&rfkill_global_mutex);

	rfkill_sync(rfkill);

	mutex_unlock(&rfkill_global_mutex);



	return sysfs_emit(buf, "%d\n", user_state_from_blocked(rfkill->state));

}
@@ -805,6 +826,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr, 
		return -EINVAL;



	mutex_lock(&rfkill_global_mutex);

	rfkill_sync(rfkill);

	rfkill_set_block(rfkill, state == RFKILL_USER_STATE_SOFT_BLOCKED);

	mutex_unlock(&rfkill_global_mutex);
@@ -1032,14 +1054,10 @@ static void rfkill_uevent_work(struct work_struct *work) 


static void rfkill_sync_work(struct work_struct *work)

{

	struct rfkill *rfkill;

	bool cur;



	rfkill = container_of(work, struct rfkill, sync_work);

	struct rfkill *rfkill = container_of(work, struct rfkill, sync_work);



	mutex_lock(&rfkill_global_mutex);

	cur = rfkill_global_states[rfkill->type].cur;

	rfkill_set_block(rfkill, cur);

	rfkill_sync(rfkill);

	mutex_unlock(&rfkill_global_mutex);

}
@@ -1087,6 +1105,7 @@ int __must_check rfkill_register(struct rfkill *rfkill) 
			round_jiffies_relative(POLL_INTERVAL));



	if (!rfkill->persistent || rfkill_epo_lock_active) {

		rfkill->need_sync = true;

		schedule_work(&rfkill->sync_work);

	} else {

#ifdef CONFIG_RFKILL_INPUT
@@ -1171,6 +1190,7 @@ static int rfkill_fop_open(struct inode *inode, struct file *file) 
		ev = kzalloc(sizeof(*ev), GFP_KERNEL);

		if (!ev)

			goto free;

		rfkill_sync(rfkill);

		rfkill_fill_event(&ev->ev, rfkill, RFKILL_OP_ADD);

		list_add_tail(&ev->list, &data->events);

	}