On Sat, Aug 8, 2009 at 1:46 PM, Alexey Klimov<klimov.linux@xxxxxxxxx> wrote:
> Small cleanup of amradio_setfreq(). No need to pass radio->curfreq value
> to this function.
>
> Signed-off-by: Alexey Klimov <klimov.linux@xxxxxxxxx>
>
> --
> diff -r 5f3329bebfe4 linux/drivers/media/radio/radio-mr800.c
> --- a/linux/drivers/media/radio/radio-mr800.c Wed Jul 29 12:36:46 2009 +0400
> +++ b/linux/drivers/media/radio/radio-mr800.c Wed Jul 29 12:41:51 2009 +0400
> @@ -202,11 +202,11 @@
> }
>
> /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
> -static int amradio_setfreq(struct amradio_device *radio, int freq)
> +static int amradio_setfreq(struct amradio_device *radio)
> {
> int retval;
> int size;
> - unsigned short freq_send = 0x10 + (freq >> 3) / 25;
> + unsigned short freq_send = 0x10 + (radio->curfreq >> 3) / 25;
I suspect there may be race conditions here. Once again you're reading
a value without first acquiring the lock. Since this is another
utility function, the lock should probably be held _before_ calling
this function and any locking in this function should be removed.
Adding a BUG_ON(!is_mutex_locked(&radio->lock)) should probably be
added as well.
>
> /* safety check */
> if (radio->removed)
> @@ -413,7 +413,7 @@
> radio->curfreq = f->frequency;
> mutex_unlock(&radio->lock);
>
> - retval = amradio_setfreq(radio, radio->curfreq);
> + retval = amradio_setfreq(radio);
> if (retval < 0)
> amradio_dev_warn(&radio->videodev->dev,
> "set frequency failed\n");
>
>
>
> --
> Best regards, Klimov Alexey
>
> --
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Regards,
David Ellingsworth
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