ALSA: core: check for underflow in snd_pcm_sw_params()

As far as I can see, having an invalid ->tstamp_mode is harmless, but
adding a check silences a static checker warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 75888dd38a7fc87acf5fcd7789570ad353dce482..4863af5e7b26638961aeda05f6595e99e0bdd604 100644 (file)
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -650,7 +650,8 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
        }
        snd_pcm_stream_unlock_irq(substream);
 
-       if (params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
+       if (params->tstamp_mode < 0 ||
+           params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
                return -EINVAL;
        if (params->proto >= SNDRV_PROTOCOL_VERSION(2, 0, 12) &&
            params->tstamp_type > SNDRV_PCM_TSTAMP_TYPE_LAST)