[media] cx231xx: cx231xx_devused is racy

cx231xx_devused is racy. Re-implement it in a proper way,
to remove the risk of mangling it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 18 insertions, 18 deletions

diff --git a/drivers/media/video/cx231xx/cx231xx-cards.c b/drivers/media/video/cx231xx/cx231xx-cards.c
index bd82f017ccdf..1f2fbbfebc76 100644
--- a/drivers/media/video/cx231xx/cx231xx-cards.c
+++ b/drivers/media/video/cx231xx/cx231xx-cards.c
@@ -854,7 +854,7 @@ void cx231xx_release_resources(struct cx231xx *dev)
         usb_put_dev(dev->udev);
 
         /* Mark device as unused */
-        cx231xx_devused &= ~(1 << dev->devno);
+        clear_bit(dev->devno, &cx231xx_devused);
 
         kfree(dev->video_mode.alt_max_pkt_size);
         kfree(dev->vbi_mode.alt_max_pkt_size);
@@ -1039,21 +1039,21 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
                 return -ENODEV;
 
         /* Check to see next free device and mark as used */
-        nr = find_first_zero_bit(&cx231xx_devused, CX231XX_MAXBOARDS);
-        cx231xx_devused |= 1 << nr;
-
-        if (nr >= CX231XX_MAXBOARDS) {
-                cx231xx_err(DRIVER_NAME
-                 ": Supports only %i cx231xx boards.\n", CX231XX_MAXBOARDS);
-                cx231xx_devused &= ~(1 << nr);
-                return -ENOMEM;
-        }
+        do {
+                nr = find_first_zero_bit(&cx231xx_devused, CX231XX_MAXBOARDS);
+                if (nr >= CX231XX_MAXBOARDS) {
+                        /* No free device slots */
+                        cx231xx_err(DRIVER_NAME ": Supports only %i devices.\n",
+                                        CX231XX_MAXBOARDS);
+                        return -ENOMEM;
+                }
+        } while (test_and_set_bit(nr, &cx231xx_devused));
 
         /* allocate memory for our device state and initialize it */
         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
         if (dev == NULL) {
                 cx231xx_err(DRIVER_NAME ": out of memory!\n");
-                cx231xx_devused &= ~(1 << nr);
+                clear_bit(dev->devno, &cx231xx_devused);
                 return -ENOMEM;
         }
 
@@ -1129,7 +1129,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
         if (assoc_desc->bFirstInterface != ifnum) {
                 cx231xx_err(DRIVER_NAME ": Not found "
                             "matching IAD interface\n");
-                cx231xx_devused &= ~(1 << nr);
+                clear_bit(dev->devno, &cx231xx_devused);
                 kfree(dev);
                 dev = NULL;
                 return -ENODEV;
@@ -1148,7 +1148,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
         retval = v4l2_device_register(&interface->dev, &dev->v4l2_dev);
         if (retval) {
                 cx231xx_errdev("v4l2_device_register failed\n");
-                cx231xx_devused &= ~(1 << nr);
+                clear_bit(dev->devno, &cx231xx_devused);
                 kfree(dev);
                 dev = NULL;
                 return -EIO;
@@ -1156,7 +1156,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
         /* allocate device struct */
         retval = cx231xx_init_dev(&dev, udev, nr);
         if (retval) {
-                cx231xx_devused &= ~(1 << dev->devno);
+                clear_bit(dev->devno, &cx231xx_devused);
                 v4l2_device_unregister(&dev->v4l2_dev);
                 kfree(dev);
                 dev = NULL;
@@ -1181,7 +1181,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
 
         if (dev->video_mode.alt_max_pkt_size == NULL) {
                 cx231xx_errdev("out of memory!\n");
-                cx231xx_devused &= ~(1 << nr);
+                clear_bit(dev->devno, &cx231xx_devused);
                 v4l2_device_unregister(&dev->v4l2_dev);
                 kfree(dev);
                 dev = NULL;
@@ -1215,7 +1215,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
 
         if (dev->vbi_mode.alt_max_pkt_size == NULL) {
                 cx231xx_errdev("out of memory!\n");
-                cx231xx_devused &= ~(1 << nr);
+                clear_bit(dev->devno, &cx231xx_devused);
                 v4l2_device_unregister(&dev->v4l2_dev);
                 kfree(dev);
                 dev = NULL;
@@ -1250,7 +1250,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
 
         if (dev->sliced_cc_mode.alt_max_pkt_size == NULL) {
                 cx231xx_errdev("out of memory!\n");
-                cx231xx_devused &= ~(1 << nr);
+                clear_bit(dev->devno, &cx231xx_devused);
                 v4l2_device_unregister(&dev->v4l2_dev);
                 kfree(dev);
                 dev = NULL;
@@ -1286,7 +1286,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
 
                 if (dev->ts1_mode.alt_max_pkt_size == NULL) {
                         cx231xx_errdev("out of memory!\n");
-                        cx231xx_devused &= ~(1 << nr);
+                        clear_bit(dev->devno, &cx231xx_devused);
                         v4l2_device_unregister(&dev->v4l2_dev);
                         kfree(dev);
                         dev = NULL;