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Subject[34-longterm 004/247] ALSA: snd-usb-us122l: Fix missing NULL checks
Date
From: Karsten Wiese <fzu@wemgehoertderstaat.de>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit cdce2db74e156fbd9a2dc3c7b246166f8b70955b upstream.

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
sound/usb/usx2y/us122l.c | 41 ++++++++++++++++++++---------------------
1 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
index 9ca9a13..886427b 100644
--- a/sound/usb/usx2y/us122l.c
+++ b/sound/usb/usx2y/us122l.c
@@ -272,29 +272,26 @@ 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;
}
@@ -380,6 +377,7 @@ 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;
@@ -425,18 +423,18 @@ 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;
@@ -447,6 +445,7 @@ unlock:
mutex_unlock(&us122l->mutex);
free:
kfree(cfg);
+ wake_up_all(&us122l->sk.sleep);
return err;
}

--
1.7.4.4


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