[alsa-devel] [PATCH 2/4] ALSA: usb-audio: Fix races at disconnection (v2)
Takashi Iwai
tiwai at suse.de
Mon Oct 15 13:02:43 CEST 2012
Close some races at disconnection of a USB audio device by adding the
chip->shutdown_mutex and chip->shutdown check at appropriate places.
The spots to put bandaids are:
- PCM prepare, hw_params and hw_free
- where the usb device is accessed for communication or get speed, in
mixer.c and others; the device speed is now cached in subs->speed
instead of accessing to chip->dev
The accesses in PCM open and close don't need the mutex protection
because these are already handled in the core PCM disconnection code.
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
v1->v2: fix unbalanced mutex_unlock in mixer.c
sound/usb/card.h | 1 +
sound/usb/mixer.c | 65 ++++++++++++++++++++++++++++++++++++------------------
sound/usb/pcm.c | 49 ++++++++++++++++++++++++++--------------
sound/usb/proc.c | 4 ++--
sound/usb/stream.c | 1 +
5 files changed, 79 insertions(+), 41 deletions(-)
diff --git a/sound/usb/card.h b/sound/usb/card.h
index afa4f9e..814cb35 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -126,6 +126,7 @@ struct snd_usb_substream {
struct snd_usb_endpoint *sync_endpoint;
unsigned long flags;
bool need_setup_ep; /* (re)configure EP at prepare? */
+ unsigned int speed; /* USB_SPEED_XXX */
u64 formats; /* format bitmasks (all or'ed) */
unsigned int num_formats; /* number of supported audio formats (list) */
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index fe56c9d..c2ef11c 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -287,25 +287,32 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v
unsigned char buf[2];
int val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
int timeout = 10;
- int err;
+ int idx = 0, err;
err = snd_usb_autoresume(cval->mixer->chip);
if (err < 0)
return -EIO;
+ mutex_lock(&chip->shutdown_mutex);
while (timeout-- > 0) {
+ if (chip->shutdown)
+ break;
+ idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
if (snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), request,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
- validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),
- buf, val_len) >= val_len) {
+ validx, idx, buf, val_len) >= val_len) {
*value_ret = convert_signed_value(cval, snd_usb_combine_bytes(buf, val_len));
- snd_usb_autosuspend(cval->mixer->chip);
- return 0;
+ err = 0;
+ goto out;
}
}
- snd_usb_autosuspend(cval->mixer->chip);
snd_printdd(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
- request, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8), cval->val_type);
- return -EINVAL;
+ request, validx, idx, cval->val_type);
+ err = -EINVAL;
+
+ out:
+ mutex_unlock(&chip->shutdown_mutex);
+ snd_usb_autosuspend(cval->mixer->chip);
+ return err;
}
static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int validx, int *value_ret)
@@ -313,7 +320,7 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
struct snd_usb_audio *chip = cval->mixer->chip;
unsigned char buf[2 + 3*sizeof(__u16)]; /* enough space for one range */
unsigned char *val;
- int ret, size;
+ int idx = 0, ret, size;
__u8 bRequest;
if (request == UAC_GET_CUR) {
@@ -330,16 +337,22 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
if (ret)
goto error;
- ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
+ mutex_lock(&chip->shutdown_mutex);
+ if (chip->shutdown)
+ ret = -ENODEV;
+ else {
+ idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
+ ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
- validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),
- buf, size);
+ validx, idx, buf, size);
+ }
+ mutex_unlock(&chip->shutdown_mutex);
snd_usb_autosuspend(chip);
if (ret < 0) {
error:
snd_printk(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
- request, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8), cval->val_type);
+ request, validx, idx, cval->val_type);
return ret;
}
@@ -417,7 +430,7 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
{
struct snd_usb_audio *chip = cval->mixer->chip;
unsigned char buf[2];
- int val_len, err, timeout = 10;
+ int idx = 0, val_len, err, timeout = 10;
if (cval->mixer->protocol == UAC_VERSION_1) {
val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
@@ -440,19 +453,27 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
err = snd_usb_autoresume(chip);
if (err < 0)
return -EIO;
- while (timeout-- > 0)
+ mutex_lock(&chip->shutdown_mutex);
+ while (timeout-- > 0) {
+ if (chip->shutdown)
+ break;
+ idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
if (snd_usb_ctl_msg(chip->dev,
usb_sndctrlpipe(chip->dev, 0), request,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
- validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),
- buf, val_len) >= 0) {
- snd_usb_autosuspend(chip);
- return 0;
+ validx, idx, buf, val_len) >= 0) {
+ err = 0;
+ goto out;
}
- snd_usb_autosuspend(chip);
+ }
snd_printdd(KERN_ERR "cannot set ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d, data = %#x/%#x\n",
- request, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8), cval->val_type, buf[0], buf[1]);
- return -EINVAL;
+ request, validx, idx, cval->val_type, buf[0], buf[1]);
+ err = -EINVAL;
+
+ out:
+ mutex_unlock(&chip->shutdown_mutex);
+ snd_usb_autosuspend(chip);
+ return err;
}
static int set_cur_ctl_value(struct usb_mixer_elem_info *cval, int validx, int value)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 55e19e1..55e741c 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -71,6 +71,8 @@ static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream
unsigned int hwptr_done;
subs = (struct snd_usb_substream *)substream->runtime->private_data;
+ if (subs->stream->chip->shutdown)
+ return SNDRV_PCM_POS_XRUN;
spin_lock(&subs->lock);
hwptr_done = subs->hwptr_done;
substream->runtime->delay = snd_usb_pcm_delay(subs,
@@ -444,7 +446,6 @@ static int configure_endpoint(struct snd_usb_substream *subs)
{
int ret;
- mutex_lock(&subs->stream->chip->shutdown_mutex);
/* format changed */
stop_endpoints(subs, 0, 0, 0);
ret = snd_usb_endpoint_set_params(subs->data_endpoint,
@@ -455,7 +456,7 @@ static int configure_endpoint(struct snd_usb_substream *subs)
subs->cur_audiofmt,
subs->sync_endpoint);
if (ret < 0)
- goto unlock;
+ return ret;
if (subs->sync_endpoint)
ret = snd_usb_endpoint_set_params(subs->data_endpoint,
@@ -465,9 +466,6 @@ static int configure_endpoint(struct snd_usb_substream *subs)
subs->cur_rate,
subs->cur_audiofmt,
NULL);
-
-unlock:
- mutex_unlock(&subs->stream->chip->shutdown_mutex);
return ret;
}
@@ -505,7 +503,13 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
return -EINVAL;
}
- if ((ret = set_format(subs, fmt)) < 0)
+ mutex_lock(&subs->stream->chip->shutdown_mutex);
+ if (subs->stream->chip->shutdown)
+ ret = -ENODEV;
+ else
+ ret = set_format(subs, fmt);
+ mutex_unlock(&subs->stream->chip->shutdown_mutex);
+ if (ret < 0)
return ret;
subs->interface = fmt->iface;
@@ -528,8 +532,10 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
subs->cur_rate = 0;
subs->period_bytes = 0;
mutex_lock(&subs->stream->chip->shutdown_mutex);
- stop_endpoints(subs, 0, 1, 1);
- deactivate_endpoints(subs);
+ if (!subs->stream->chip->shutdown) {
+ stop_endpoints(subs, 0, 1, 1);
+ deactivate_endpoints(subs);
+ }
mutex_unlock(&subs->stream->chip->shutdown_mutex);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
@@ -552,12 +558,19 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
return -ENXIO;
}
- if (snd_BUG_ON(!subs->data_endpoint))
- return -EIO;
+ mutex_lock(&subs->stream->chip->shutdown_mutex);
+ if (subs->stream->chip->shutdown) {
+ ret = -ENODEV;
+ goto unlock;
+ }
+ if (snd_BUG_ON(!subs->data_endpoint)) {
+ ret = -EIO;
+ goto unlock;
+ }
ret = set_format(subs, subs->cur_audiofmt);
if (ret < 0)
- return ret;
+ goto unlock;
iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
@@ -567,12 +580,12 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
subs->cur_audiofmt,
subs->cur_rate);
if (ret < 0)
- return ret;
+ goto unlock;
if (subs->need_setup_ep) {
ret = configure_endpoint(subs);
if (ret < 0)
- return ret;
+ goto unlock;
subs->need_setup_ep = false;
}
@@ -592,9 +605,11 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
/* for playback, submit the URBs now; otherwise, the first hwptr_done
* updates for all URBs would happen at the same time when starting */
if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
- return start_endpoints(subs, 1);
+ ret = start_endpoints(subs, 1);
- return 0;
+ unlock:
+ mutex_unlock(&subs->stream->chip->shutdown_mutex);
+ return ret;
}
static struct snd_pcm_hardware snd_usb_hardware =
@@ -647,7 +662,7 @@ static int hw_check_valid_format(struct snd_usb_substream *subs,
return 0;
}
/* check whether the period time is >= the data packet interval */
- if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL) {
+ if (subs->speed != USB_SPEED_FULL) {
ptime = 125 * (1 << fp->datainterval);
if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
hwc_debug(" > check: ptime %u > max %u\n", ptime, pt->max);
@@ -925,7 +940,7 @@ static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substre
return err;
param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
- if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
+ if (subs->speed == USB_SPEED_FULL)
/* full speed devices have fixed data packet interval */
ptmin = 1000;
if (ptmin == 1000)
diff --git a/sound/usb/proc.c b/sound/usb/proc.c
index ebc1a5b..d218f76 100644
--- a/sound/usb/proc.c
+++ b/sound/usb/proc.c
@@ -108,7 +108,7 @@ static void proc_dump_substream_formats(struct snd_usb_substream *subs, struct s
}
snd_iprintf(buffer, "\n");
}
- if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL)
+ if (subs->speed != USB_SPEED_FULL)
snd_iprintf(buffer, " Data packet interval: %d us\n",
125 * (1 << fp->datainterval));
// snd_iprintf(buffer, " Max Packet Size = %d\n", fp->maxpacksize);
@@ -124,7 +124,7 @@ static void proc_dump_ep_status(struct snd_usb_substream *subs,
return;
snd_iprintf(buffer, " Packet Size = %d\n", ep->curpacksize);
snd_iprintf(buffer, " Momentary freq = %u Hz (%#x.%04x)\n",
- snd_usb_get_speed(subs->dev) == USB_SPEED_FULL
+ subs->speed == USB_SPEED_FULL
? get_full_speed_hz(ep->freqm)
: get_high_speed_hz(ep->freqm),
ep->freqm >> 16, ep->freqm & 0xffff);
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 083ed81..1de0c8c 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -90,6 +90,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
subs->direction = stream;
subs->dev = as->chip->dev;
subs->txfr_quirk = as->chip->txfr_quirk;
+ subs->speed = snd_usb_get_speed(subs->dev);
snd_usb_set_pcm_ops(as->pcm, stream);
--
1.7.12.3
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