ALSA: snd-usb-us122l: Fix missing NULL checks

Fix missing NULL checks in usb_stream_hwdep_poll() and usb_stream_hwdep_ioctl().
Wake up poll waiters before returning from usb_stream_hwdep_ioctl().

Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
Cc: stable@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 20 insertions, 21 deletions

diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
index 6ef68e42138e..084e6fc8d5bf 100644
--- a/sound/usb/usx2y/us122l.c
+++ b/sound/usb/usx2y/us122l.c
@@ -273,29 +273,26 @@ static unsigned int usb_stream_hwdep_poll(struct snd_hwdep *hw,
                                           struct file *file, poll_table *wait)
 {
         struct us122l   *us122l = hw->private_data;
-        struct usb_stream *s = us122l->sk.s;
         unsigned        *polled;
         unsigned int    mask;
 
         poll_wait(file, &us122l->sk.sleep, wait);
 
-        switch (s->state) {
-        case usb_stream_ready:
-                if (us122l->first == file)
-                        polled = &s->periods_polled;
-                else
-                        polled = &us122l->second_periods_polled;
-                if (*polled != s->periods_done) {
-                        *polled = s->periods_done;
-                        mask = POLLIN | POLLOUT | POLLWRNORM;
-                        break;
+        mask = POLLIN | POLLOUT | POLLWRNORM | POLLERR;
+        if (mutex_trylock(&us122l->mutex)) {
+                struct usb_stream *s = us122l->sk.s;
+                if (s && s->state == usb_stream_ready) {
+                        if (us122l->first == file)
+                                polled = &s->periods_polled;
+                        else
+                                polled = &us122l->second_periods_polled;
+                        if (*polled != s->periods_done) {
+                                *polled = s->periods_done;
+                                mask = POLLIN | POLLOUT | POLLWRNORM;
+                        } else
+                                mask = 0;
                 }
-                /* Fall through */
-                mask = 0;
-                break;
-        default:
-                mask = POLLIN | POLLOUT | POLLWRNORM | POLLERR;
-                break;
+                mutex_unlock(&us122l->mutex);
         }
         return mask;
 }
@@ -381,6 +378,7 @@ static int usb_stream_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
 {
         struct usb_stream_config *cfg;
         struct us122l *us122l = hw->private_data;
+        struct usb_stream *s;
         unsigned min_period_frames;
         int err = 0;
         bool high_speed;
@@ -426,18 +424,18 @@ static int usb_stream_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
         snd_power_wait(hw->card, SNDRV_CTL_POWER_D0);
 
         mutex_lock(&us122l->mutex);
+        s = us122l->sk.s;
         if (!us122l->master)
                 us122l->master = file;
         else if (us122l->master != file) {
-                if (memcmp(cfg, &us122l->sk.s->cfg, sizeof(*cfg))) {
+                if (!s || memcmp(cfg, &s->cfg, sizeof(*cfg))) {
                         err = -EIO;
                         goto unlock;
                 }
                 us122l->slave = file;
         }
-        if (!us122l->sk.s ||
-            memcmp(cfg, &us122l->sk.s->cfg, sizeof(*cfg)) ||
-            us122l->sk.s->state == usb_stream_xrun) {
+        if (!s || memcmp(cfg, &s->cfg, sizeof(*cfg)) ||
+            s->state == usb_stream_xrun) {
                 us122l_stop(us122l);
                 if (!us122l_start(us122l, cfg->sample_rate, cfg->period_frames))
                         err = -EIO;
@@ -448,6 +446,7 @@ unlock:
         mutex_unlock(&us122l->mutex);
 free:
         kfree(cfg);
+        wake_up_all(&us122l->sk.sleep);
         return err;
 }