linux-kernel - [PATCH v4 26/40] media: em28xx: cx231xx: optimize drivers by using find_and_set

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Date: Thu, 20 Jun 2024 10:56:49 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Yury Norov <yury.norov@...il.com>,
	linux-media@...r.kernel.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>,
	Hans Verkuil <hverkuil-cisco@...all.nl>
Subject: [PATCH v4 26/40] media: em28xx: cx231xx: optimize drivers by using find_and_set_bit()

Functions in the media/usb drivers opencode find_and_set_bit(). Simplify
them by using the function.

Signed-off-by: Yury Norov <yury.norov@...il.com>
Acked-by: Hans Verkuil <hverkuil-cisco@...all.nl>
---
 drivers/media/usb/cx231xx/cx231xx-cards.c | 17 +++++-----
 drivers/media/usb/em28xx/em28xx-cards.c   | 38 ++++++++++-------------
 2 files changed, 23 insertions(+), 32 deletions(-)

diff --git a/drivers/media/usb/cx231xx/cx231xx-cards.c b/drivers/media/usb/cx231xx/cx231xx-cards.c
index 92efe6c1f47b..8bdfbc4454f1 100644
--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -9,6 +9,7 @@
  */
 
 #include "cx231xx.h"
+#include <linux/find_atomic.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -1708,16 +1709,12 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
 		return -ENODEV;
 
 	/* Check to see next free device and mark as used */
-	do {
-		nr = find_first_zero_bit(&cx231xx_devused, CX231XX_MAXBOARDS);
-		if (nr >= CX231XX_MAXBOARDS) {
-			/* No free device slots */
-			dev_err(d,
-				"Supports only %i devices.\n",
-				CX231XX_MAXBOARDS);
-			return -ENOMEM;
-		}
-	} while (test_and_set_bit(nr, &cx231xx_devused));
+	nr = find_and_set_bit(&cx231xx_devused, CX231XX_MAXBOARDS);
+	if (nr >= CX231XX_MAXBOARDS) {
+		/* No free device slots */
+		dev_err(d, "Supports only %i devices.\n", CX231XX_MAXBOARDS);
+		return -ENOMEM;
+	}
 
 	udev = usb_get_dev(interface_to_usbdev(interface));
 
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index bae76023cf71..59e6d7f894ad 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -11,6 +11,7 @@
 
 #include "em28xx.h"
 
+#include <linux/find_atomic.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -3684,17 +3685,14 @@ static int em28xx_duplicate_dev(struct em28xx *dev)
 		return -ENOMEM;
 	}
 	/* Check to see next free device and mark as used */
-	do {
-		nr = find_first_zero_bit(em28xx_devused, EM28XX_MAXBOARDS);
-		if (nr >= EM28XX_MAXBOARDS) {
-			/* No free device slots */
-			dev_warn(&dev->intf->dev, ": Supports only %i em28xx boards.\n",
-				 EM28XX_MAXBOARDS);
-			kfree(sec_dev);
-			dev->dev_next = NULL;
-			return -ENOMEM;
-		}
-	} while (test_and_set_bit(nr, em28xx_devused));
+	nr = find_and_set_bit(em28xx_devused, EM28XX_MAXBOARDS);
+	if (nr >= EM28XX_MAXBOARDS) {
+		/* No free device slots */
+		dev_warn(&dev->intf->dev, ": Supports only %i em28xx boards.\n", EM28XX_MAXBOARDS);
+		kfree(sec_dev);
+		dev->dev_next = NULL;
+		return -ENOMEM;
+	}
 	sec_dev->devno = nr;
 	snprintf(sec_dev->name, 28, "em28xx #%d", nr);
 	sec_dev->dev_next = NULL;
@@ -3827,17 +3825,13 @@ static int em28xx_usb_probe(struct usb_interface *intf,
 	udev = usb_get_dev(interface_to_usbdev(intf));
 
 	/* Check to see next free device and mark as used */
-	do {
-		nr = find_first_zero_bit(em28xx_devused, EM28XX_MAXBOARDS);
-		if (nr >= EM28XX_MAXBOARDS) {
-			/* No free device slots */
-			dev_err(&intf->dev,
-				"Driver supports up to %i em28xx boards.\n",
-			       EM28XX_MAXBOARDS);
-			retval = -ENOMEM;
-			goto err_no_slot;
-		}
-	} while (test_and_set_bit(nr, em28xx_devused));
+	nr = find_and_set_bit(em28xx_devused, EM28XX_MAXBOARDS);
+	if (nr >= EM28XX_MAXBOARDS) {
+		/* No free device slots */
+		dev_err(&intf->dev, "Driver supports up to %i em28xx boards.\n", EM28XX_MAXBOARDS);
+		retval = -ENOMEM;
+		goto err_no_slot;
+	}
 
 	/* Don't register audio interfaces */
 	if (intf->altsetting[0].desc.bInterfaceClass == USB_CLASS_AUDIO) {
-- 
2.43.0