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From:   Ulf Hansson <ulf.hansson@linaro.org>
To:     "Rafael J . Wysocki" <rjw@rjwysocki.net>, linux-pm@vger.kernel.org
Cc:     Ulf Hansson <ulf.hansson@linaro.org>,
        Saravana Kannan <saravanak@google.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Tony Lindgren <tony@atomide.com>,
        Kevin Hilman <khilman@kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/3] PM: runtime: Improve path in rpm_idle() when no callback
Date:   Tue,  8 Jun 2021 11:02:48 +0200
Message-Id: <20210608090250.85256-2-ulf.hansson@linaro.org>
In-Reply-To: <20210608090250.85256-1-ulf.hansson@linaro.org>
References: <20210608090250.85256-1-ulf.hansson@linaro.org>
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When pm_runtime_no_callbacks() has been called for a struct device to set
the dev->power.no_callbacks flag for it, it enables rpm_idle() to take a
slightly quicker path by assuming that a ->runtime_idle() callback would
have returned 0 to indicate success.

A device that does not have the dev->power.no_callbacks flag set for it,
may still be missing a corresponding ->runtime_idle() callback, in which
case the slower path in rpm_idle() is taken. Let's improve the behaviour
for this case, by aligning code to the quicker path.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Changes in v2:
	- None.

---
 drivers/base/power/runtime.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index b570848d23e0..68bebbf81347 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -446,7 +446,10 @@ static int rpm_idle(struct device *dev, int rpmflags)
 	/* Pending requests need to be canceled. */
 	dev->power.request = RPM_REQ_NONE;
 
-	if (dev->power.no_callbacks)
+	callback = RPM_GET_CALLBACK(dev, runtime_idle);
+
+	/* If no callback assume success. */
+	if (!callback || dev->power.no_callbacks)
 		goto out;
 
 	/* Carry out an asynchronous or a synchronous idle notification. */
@@ -462,10 +465,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
 
 	dev->power.idle_notification = true;
 
-	callback = RPM_GET_CALLBACK(dev, runtime_idle);
-
-	if (callback)
-		retval = __rpm_callback(callback, dev);
+	retval = __rpm_callback(callback, dev);
 
 	dev->power.idle_notification = false;
 	wake_up_all(&dev->power.wait_queue);
-- 
2.25.1