linux-kernel - [PATCH v4 30/40] ALSA: use atomic find

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Date: Thu, 20 Jun 2024 10:56:53 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Jaroslav Kysela <perex@...ex.cz>,
	Takashi Iwai <tiwai@...e.com>,
	Daniel Mack <zonque@...il.com>,
	Cezary Rojewski <cezary.rojewski@...el.com>,
	Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
	Yury Norov <yury.norov@...il.com>,
	Kees Cook <keescook@...omium.org>,
	linux-sound@...r.kernel.org,
	alsa-devel@...a-project.org
Cc: Alexey Klimov <alexey.klimov@...aro.org>,
	Bart Van Assche <bvanassche@....org>,
	Jan Kara <jack@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Wilcox <willy@...radead.org>,
	Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Sergey Shtylyov <s.shtylyov@....ru>,
	Takashi Iwai <tiwai@...e.de>
Subject: [PATCH v4 30/40] ALSA: use atomic find_bit() functions where applicable

ALSA code tests each bit in bitmaps in a for-loop. Switch it to
using dedicated atomic find_bit() API.

Signed-off-by: Yury Norov <yury.norov@...il.com>
Acked-by: Takashi Iwai <tiwai@...e.de>
---
 sound/pci/hda/hda_codec.c |  8 ++++----
 sound/usb/caiaq/audio.c   | 14 ++++++--------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 325e8f0b99a8..7201afa82990 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -7,6 +7,7 @@
 
 #include <linux/init.h>
 #include <linux/delay.h>
+#include <linux/find_atomic.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/module.h>
@@ -3263,10 +3264,9 @@ static int get_empty_pcm_device(struct hda_bus *bus, unsigned int type)
 
 #ifdef CONFIG_SND_DYNAMIC_MINORS
 	/* non-fixed slots starting from 10 */
-	for (i = 10; i < 32; i++) {
-		if (!test_and_set_bit(i, bus->pcm_dev_bits))
-			return i;
-	}
+	i = find_and_set_next_bit(bus->pcm_dev_bits, 32, 10);
+	if (i < 32)
+		return i;
 #endif
 
 	dev_warn(bus->card->dev, "Too many %s devices\n",
diff --git a/sound/usb/caiaq/audio.c b/sound/usb/caiaq/audio.c
index 4981753652a7..93ecd5cfcb7d 100644
--- a/sound/usb/caiaq/audio.c
+++ b/sound/usb/caiaq/audio.c
@@ -4,6 +4,7 @@
 */
 
 #include <linux/device.h>
+#include <linux/find_atomic.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/init.h>
@@ -610,7 +611,7 @@ static void read_completed(struct urb *urb)
 	struct snd_usb_caiaq_cb_info *info = urb->context;
 	struct snd_usb_caiaqdev *cdev;
 	struct device *dev;
-	struct urb *out = NULL;
+	struct urb *out;
 	int i, frame, len, send_it = 0, outframe = 0;
 	unsigned long flags;
 	size_t offset = 0;
@@ -625,17 +626,14 @@ static void read_completed(struct urb *urb)
 		return;
 
 	/* find an unused output urb that is unused */
-	for (i = 0; i < N_URBS; i++)
-		if (test_and_set_bit(i, &cdev->outurb_active_mask) == 0) {
-			out = cdev->data_urbs_out[i];
-			break;
-		}
-
-	if (!out) {
+	i = find_and_set_bit(&cdev->outurb_active_mask, N_URBS);
+	if (i >= N_URBS) {
 		dev_err(dev, "Unable to find an output urb to use\n");
 		goto requeue;
 	}
 
+	out = cdev->data_urbs_out[i];
+
 	/* read the recently received packet and send back one which has
 	 * the same layout */
 	for (frame = 0; frame < FRAMES_PER_URB; frame++) {
-- 
2.43.0