[patch review 6/6] radio-mr800: redesign radio->users counter

[Alexey Klimov]

Redesign radio->users counter. Don't allow more that 5 users on radio in
usb_amradio_open() and don't stop radio device if other userspace
application uses it in usb_amradio_close().

Signed-off-by: Alexey Klimov <klimov.li...@gmail.com>

--
diff -r c2dd9da28106 linux/drivers/media/radio/radio-mr800.c
--- a/linux/drivers/media/radio/radio-mr800.c   Sat Aug 08 17:28:18 2009 +0400
+++ b/linux/drivers/media/radio/radio-mr800.c   Sat Aug 08 18:12:01 2009 +0400
@@ -540,7 +540,13 @@
 {
        struct amradio_device *radio = video_get_drvdata(video_devdata(file));
 
-       radio->users = 1;
+       /* don't allow more than 5 users on radio */
+       if (radio->users > 4)
+               return -EBUSY;
+
+       mutex_lock(&radio->lock);
+       radio->users++;
+       mutex_unlock(&radio->lock);
 
        return 0;
 }
@@ -554,9 +560,20 @@
                return -ENODEV;
 
        mutex_lock(&radio->lock);
-       radio->users = 0;
+       radio->users--;
        mutex_unlock(&radio->lock);
 
+       /* In case several userspace applications opened the radio
+        * and one of them closes and stops it,
+        * we check if others use it and if they do we start the radio again. */
+       if (radio->users && radio->status == AMRADIO_STOP) {
+               int retval;
+               retval = amradio_set_mute(radio, AMRADIO_START);
+               if (retval < 0)
+                       dev_warn(&radio->videodev->dev,
+                               "amradio_start failed\n");
+       }
+
        return 0;
 }
 


-- 
Best regards, Klimov Alexey

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