[alsa-devel] [PATCH 4/4] ALSA: usb-audio: Fix races at disconnection in mixer_quirks.c

[Takashi Iwai]

Similar like the previous commit, cover with chip->shutdown_rwsem
and chip->shutdown checks.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/usb/mixer_quirks.c | 58 ++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 690000d..ae2b714 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -283,6 +283,11 @@ static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol, struct snd_ctl_e
 	if (value > 1)
 		return -EINVAL;
 	changed = value != mixer->audigy2nx_leds[index];
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown) {
+		err = -ENODEV;
+		goto out;
+	}
 	if (mixer->chip->usb_id == USB_ID(0x041e, 0x3042))
 		err = snd_usb_ctl_msg(mixer->chip->dev,
 			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
@@ -299,6 +304,8 @@ static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol, struct snd_ctl_e
 			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      value, index + 2, NULL, 0);
+ out:
+	up_read(&mixer->chip->shutdown_rwsem);
 	if (err < 0)
 		return err;
 	mixer->audigy2nx_leds[index] = value;
@@ -392,11 +399,16 @@ static void snd_audigy2nx_proc_read(struct snd_info_entry *entry,
 
 	for (i = 0; jacks[i].name; ++i) {
 		snd_iprintf(buffer, "%s: ", jacks[i].name);
-		err = snd_usb_ctl_msg(mixer->chip->dev,
+		down_read(&mixer->chip->shutdown_rwsem);
+		if (mixer->chip->shutdown)
+			err = 0;
+		else
+			err = snd_usb_ctl_msg(mixer->chip->dev,
 				      usb_rcvctrlpipe(mixer->chip->dev, 0),
 				      UAC_GET_MEM, USB_DIR_IN | USB_TYPE_CLASS |
 				      USB_RECIP_INTERFACE, 0,
 				      jacks[i].unitid << 8, buf, 3);
+		up_read(&mixer->chip->shutdown_rwsem);
 		if (err == 3 && (buf[0] == 3 || buf[0] == 6))
 			snd_iprintf(buffer, "%02x %02x\n", buf[1], buf[2]);
 		else
@@ -426,10 +438,15 @@ static int snd_xonar_u1_switch_put(struct snd_kcontrol *kcontrol,
 	else
 		new_status = old_status & ~0x02;
 	changed = new_status != old_status;
-	err = snd_usb_ctl_msg(mixer->chip->dev,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		err = -ENODEV;
+	else
+		err = snd_usb_ctl_msg(mixer->chip->dev,
 			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x08,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      50, 0, &new_status, 1);
+	up_read(&mixer->chip->shutdown_rwsem);
 	if (err < 0)
 		return err;
 	mixer->xonar_u1_status = new_status;
@@ -468,11 +485,17 @@ static int snd_nativeinstruments_control_get(struct snd_kcontrol *kcontrol,
 	u8 bRequest = (kcontrol->private_value >> 16) & 0xff;
 	u16 wIndex = kcontrol->private_value & 0xffff;
 	u8 tmp;
+	int ret;
 
-	int ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), bRequest,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		ret = -ENODEV;
+	else
+		ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), bRequest,
 				  USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 				  0, cpu_to_le16(wIndex),
 				  &tmp, sizeof(tmp), 1000);
+	up_read(&mixer->chip->shutdown_rwsem);
 
 	if (ret < 0) {
 		snd_printk(KERN_ERR
@@ -493,11 +516,17 @@ static int snd_nativeinstruments_control_put(struct snd_kcontrol *kcontrol,
 	u8 bRequest = (kcontrol->private_value >> 16) & 0xff;
 	u16 wIndex = kcontrol->private_value & 0xffff;
 	u16 wValue = ucontrol->value.integer.value[0];
+	int ret;
 
-	int ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), bRequest,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		ret = -ENODEV;
+	else
+		ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), bRequest,
 				  USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 				  cpu_to_le16(wValue), cpu_to_le16(wIndex),
 				  NULL, 0, 1000);
+	up_read(&mixer->chip->shutdown_rwsem);
 
 	if (ret < 0) {
 		snd_printk(KERN_ERR
@@ -656,11 +685,16 @@ static int snd_ftu_eff_switch_get(struct snd_kcontrol *kctl,
 		return -EINVAL;
 
 
-	err = snd_usb_ctl_msg(chip->dev,
+	down_read(&mixer->chip->shutdown_rwsem);
+	if (mixer->chip->shutdown)
+		err = -ENODEV;
+	else
+		err = snd_usb_ctl_msg(chip->dev,
 			usb_rcvctrlpipe(chip->dev, 0), UAC_GET_CUR,
 			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 			validx << 8, snd_usb_ctrl_intf(chip) | (id << 8),
 			value, val_len);
+	up_read(&mixer->chip->shutdown_rwsem);
 	if (err < 0)
 		return err;
 
@@ -703,11 +737,16 @@ static int snd_ftu_eff_switch_put(struct snd_kcontrol *kctl,
 
 	if (!pval->is_cached) {
 		/* Read current value */
-		err = snd_usb_ctl_msg(chip->dev,
+		down_read(&mixer->chip->shutdown_rwsem);
+		if (mixer->chip->shutdown)
+			err = -ENODEV;
+		else
+			err = snd_usb_ctl_msg(chip->dev,
 				usb_rcvctrlpipe(chip->dev, 0), UAC_GET_CUR,
 				USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 				validx << 8, snd_usb_ctrl_intf(chip) | (id << 8),
 				value, val_len);
+		up_read(&mixer->chip->shutdown_rwsem);
 		if (err < 0)
 			return err;
 
@@ -719,11 +758,16 @@ static int snd_ftu_eff_switch_put(struct snd_kcontrol *kctl,
 	if (cur_val != new_val) {
 		value[0] = new_val;
 		value[1] = 0;
-		err = snd_usb_ctl_msg(chip->dev,
+		down_read(&mixer->chip->shutdown_rwsem);
+		if (mixer->chip->shutdown)
+			err = -ENODEV;
+		else
+			err = snd_usb_ctl_msg(chip->dev,
 				usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
 				USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
 				validx << 8, snd_usb_ctrl_intf(chip) | (id << 8),
 				value, val_len);
+		up_read(&mixer->chip->shutdown_rwsem);
 		if (err < 0)
 			return err;
 
-- 
1.7.12.3