linux-kernel - [PATCH v1 3/3] ACPI: EC: Rearrange code in acpi_ec_submit

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Date:   Fri, 04 Feb 2022 18:43:14 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux ACPI <linux-acpi@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v1 3/3] ACPI: EC: Rearrange code in acpi_ec_submit_event()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Rearange acpi_ec_event_handler() so as to avoid releasing ec->lock
and acquiring it again right away in the case when ec_event_clearing
is not ACPI_EC_EVT_TIMING_EVENT.

This also reduces the number of checks done by acpi_ec_event_handler()
in that case.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/ec.c |   22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

Index: linux-pm/drivers/acpi/ec.c
===================================================================
--- linux-pm.orig/drivers/acpi/ec.c
+++ linux-pm/drivers/acpi/ec.c
@@ -1238,6 +1238,7 @@ static void acpi_ec_event_handler(struct
 		acpi_ec_submit_query(ec);
 
 		spin_lock_irq(&ec->lock);
+
 		ec->events_to_process--;
 	}
 
@@ -1246,27 +1247,30 @@ static void acpi_ec_event_handler(struct
 	 * event handling work again regardless of whether or not the query
 	 * queued up above is processed successfully.
 	 */
-	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT)
+	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
+		bool guard_timeout;
+
 		acpi_ec_complete_event(ec);
-	else
-		acpi_ec_close_event(ec);
 
-	spin_unlock_irq(&ec->lock);
+		ec_dbg_evt("Event stopped");
 
-	ec_dbg_evt("Event stopped");
+		spin_unlock_irq(&ec->lock);
+
+		guard_timeout = !!ec_guard(ec);
 
-	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT && ec_guard(ec)) {
 		spin_lock_irq(&ec->lock);
 
 		/* Take care of SCI_EVT unless someone else is doing that. */
-		if (!ec->curr)
+		if (guard_timeout && !ec->curr)
 			advance_transaction(ec, false);
+	} else {
+		acpi_ec_close_event(ec);
 
-		spin_unlock_irq(&ec->lock);
+		ec_dbg_evt("Event stopped");
 	}
 
-	spin_lock_irq(&ec->lock);
 	ec->events_in_progress--;
+
 	spin_unlock_irq(&ec->lock);
 }