Commit 68d0021f authored by Remi Pommarel's avatar Remi Pommarel Committed by Johannes Berg
Browse files

wifi: cfg80211: Add wiphy_delayed_work_pending() 



Add wiphy_delayed_work_pending() to check if any delayed work timer is
pending, that can be used to be sure that wiphy_delayed_work_queue()
won't postpone an already pending delayed work.

Signed-off-by: default avatarRemi Pommarel <repk@triplefau.lt>
Link: https://patch.msgid.link/20240924192805.13859-2-repk@triplefau.lt


[fix return value kernel-doc]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent e1a9ae3a

include/net/cfg80211.h

+44 −0
Original line number Diff line number Diff line
@@ -6129,6 +6129,50 @@ void wiphy_delayed_work_cancel(struct wiphy *wiphy, 
void wiphy_delayed_work_flush(struct wiphy *wiphy,

			      struct wiphy_delayed_work *dwork);



/**

 * wiphy_delayed_work_pending - Find out whether a wiphy delayable

 * work item is currently pending.

 *

 * @wiphy: the wiphy, for debug purposes

 * @dwork: the delayed work in question

 *

 * Return: true if timer is pending, false otherwise

 *

 * How wiphy_delayed_work_queue() works is by setting a timer which

 * when it expires calls wiphy_work_queue() to queue the wiphy work.

 * Because wiphy_delayed_work_queue() uses mod_timer(), if it is

 * called twice and the second call happens before the first call

 * deadline, the work will rescheduled for the second deadline and

 * won't run before that.

 *

 * wiphy_delayed_work_pending() can be used to detect if calling

 * wiphy_work_delayed_work_queue() would start a new work schedule

 * or delayed a previous one. As seen below it cannot be used to

 * detect precisely if the work has finished to execute nor if it

 * is currently executing.

 *

 *      CPU0                                CPU1

 * wiphy_delayed_work_queue(wk)

 *  mod_timer(wk->timer)

 *                                     wiphy_delayed_work_pending(wk) -> true

 *

 * [...]

 * expire_timers(wk->timer)

 *  detach_timer(wk->timer)

 *                                     wiphy_delayed_work_pending(wk) -> false

 *  wk->timer->function()                          |

 *   wiphy_work_queue(wk)                          | delayed work pending

 *    list_add_tail()                              | returns false but

 *    queue_work(cfg80211_wiphy_work)              | wk->func() has not

 *                                                 | been run yet

 * [...]                                           |

 *  cfg80211_wiphy_work()                          |

 *   wk->func()                                    V

 *

 */

bool wiphy_delayed_work_pending(struct wiphy *wiphy,

				struct wiphy_delayed_work *dwork);



/**

 * enum ieee80211_ap_reg_power - regulatory power for an Access Point

 *

net/wireless/core.c

+7 −0
Original line number Diff line number Diff line
@@ -1704,6 +1704,13 @@ void wiphy_delayed_work_flush(struct wiphy *wiphy, 
}

EXPORT_SYMBOL_GPL(wiphy_delayed_work_flush);



bool wiphy_delayed_work_pending(struct wiphy *wiphy,

				struct wiphy_delayed_work *dwork)

{

	return timer_pending(&dwork->timer);

}

EXPORT_SYMBOL_GPL(wiphy_delayed_work_pending);



static int __init cfg80211_init(void)

{

	int err;