Commit c793570d authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: EC: Avoid queuing unnecessary work in acpi_ec_submit_event() 



Notice that it is not necessary to queue up the event work again
if the while () loop in acpi_ec_event_handler() is still running
which is the case if nr_pending_queries is greater than 0 at the
beginning of acpi_ec_submit_event() and modify the code to avoid
doing that.

While at it, rename nr_pending_queries in struct acpi_ec to
events_to_process which actually matches the role of that field
and change its data type to unsigned int which is sufficient.

No expected functional impact.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent eafe7509

drivers/acpi/ec.c

+13 −4
Original line number Diff line number Diff line
@@ -453,7 +453,16 @@ static bool acpi_ec_submit_event(struct acpi_ec *ec) 
	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {

		ec_dbg_evt("Command(%s) submitted/blocked",

			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));

		ec->nr_pending_queries++;

		/*

		 * If events_to_process is greqter than 0 at this point, the

		 * while () loop in acpi_ec_event_handler() is still running

		 * and incrementing events_to_process will cause it to invoke

		 * acpi_ec_submit_query() once more, so it is not necessary to

		 * queue up the event work to start the same loop again.

		 */

		if (ec->events_to_process++ > 0)

			return true;



		ec->events_in_progress++;

		return queue_work(ec_wq, &ec->work);

	}
@@ -665,7 +674,7 @@ static bool advance_transaction(struct acpi_ec *ec, bool interrupt) 
	 */

	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {

		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&

		    (!ec->nr_pending_queries ||

		    (!ec->events_to_process ||

		     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {

			clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);

			acpi_ec_close_event(ec);
@@ -1223,13 +1232,13 @@ static void acpi_ec_event_handler(struct work_struct *work) 


	spin_lock_irq(&ec->lock);



	while (ec->nr_pending_queries) {

	while (ec->events_to_process) {

		spin_unlock_irq(&ec->lock);



		acpi_ec_submit_query(ec);



		spin_lock_irq(&ec->lock);

		ec->nr_pending_queries--;

		ec->events_to_process--;

	}



	/*

drivers/acpi/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -182,7 +182,7 @@ struct acpi_ec { 
	spinlock_t lock;

	struct work_struct work;

	unsigned long timestamp;

	unsigned long nr_pending_queries;

	unsigned int events_to_process;

	unsigned int events_in_progress;

	unsigned int queries_in_progress;

	bool busy_polling;