linux-kernel - [PATCH] HID: logitech-hidpp: Use 'atomic_inc

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Message-Id: <1091bc38881086be28d561adca042caba234f3f2.1627054657.git.christophe.jaillet@wanadoo.fr>
Date:   Fri, 23 Jul 2021 17:41:52 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     jikos@...nel.org, benjamin.tissoires@...hat.com
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] HID: logitech-hidpp: Use 'atomic_inc_return' instead of hand-writing it

This function logs a warning if the workqueue gets too big.
In order to save a few cycles, use 'atomic_inc_return()' instead of an
'atomic_inc()/atomic_read()' sequence.

This axes a line of code and saves a 'atomic_read()' call.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/hid/hid-logitech-hidpp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 61635e629469..a7fa35245c2e 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -2240,11 +2240,10 @@ static int hidpp_ff_queue_work(struct hidpp_ff_private_data *data, int effect_id
 	wd->size = size;
 	memcpy(wd->params, params, size);
 
-	atomic_inc(&data->workqueue_size);
+	s = atomic_inc_return(&data->workqueue_size);
 	queue_work(data->wq, &wd->work);
 
 	/* warn about excessive queue size */
-	s = atomic_read(&data->workqueue_size);
 	if (s >= 20 && s % 20 == 0)
 		hid_warn(data->hidpp->hid_dev, "Force feedback command queue contains %d commands, causing substantial delays!", s);
 
-- 
2.30.2