1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index e4c80b44b55a..e177bac777f4 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -130,6 +130,7 @@ struct usbtmc_file_data {
 	u32            timeout;
 	u8             srq_byte;
 	atomic_t       srq_asserted;
+	atomic_t       closing;
 
 	u8             eom_val;
 	u8             term_char;
@@ -193,6 +194,8 @@ static int usbtmc_open(struct inode *inode, struct file *filp)
 	mutex_lock(&data->io_mutex);
 	file_data->data = data;
 
+	atomic_set(&file_data->closing, 0);
+
 	/* copy default values from device settings */
 	file_data->timeout = USBTMC_TIMEOUT;
 	file_data->term_char = data->TermChar;
@@ -223,6 +226,7 @@ static int usbtmc_flush(struct file *file, fl_owner_t id)
 	if (file_data == NULL)
 		return -ENODEV;
 
+	atomic_set(&file_data->closing, 1);
 	data = file_data->data;
 
 	/* wait for io to stop */
@@ -576,6 +580,54 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,
 	return rv;
 }
 
+static int usbtmc488_ioctl_wait_srq(struct usbtmc_file_data *file_data,
+				    __u32 __user *arg)
+{
+	struct usbtmc_device_data *data = file_data->data;
+	struct device *dev = &data->intf->dev;
+	int rv;
+	u32 timeout;
+	unsigned long expire;
+
+	if (!data->iin_ep_present) {
+		dev_dbg(dev, "no interrupt endpoint present\n");
+		return -EFAULT;
+	}
+
+	if (get_user(timeout, arg))
+		return -EFAULT;
+
+	expire = msecs_to_jiffies(timeout);
+
+	mutex_unlock(&data->io_mutex);
+
+	rv = wait_event_interruptible_timeout(
+			data->waitq,
+			atomic_read(&file_data->srq_asserted) != 0 ||
+			atomic_read(&file_data->closing),
+			expire);
+
+	mutex_lock(&data->io_mutex);
+
+	/* Note! disconnect or close could be called in the meantime */
+	if (atomic_read(&file_data->closing) || data->zombie)
+		rv = -ENODEV;
+
+	if (rv < 0) {
+		/* dev can be invalid now! */
+		pr_debug("%s - wait interrupted %d\n", __func__, rv);
+		return rv;
+	}
+
+	if (rv == 0) {
+		dev_dbg(dev, "%s - wait timed out\n", __func__);
+		return -ETIMEDOUT;
+	}
+
+	dev_dbg(dev, "%s - srq asserted\n", __func__);
+	return 0;
+}
+
 static int usbtmc488_ioctl_simple(struct usbtmc_device_data *data,
 				void __user *arg, unsigned int cmd)
 {
@@ -2142,6 +2194,11 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		retval = usbtmc488_ioctl_trigger(file_data);
 		break;
 
+	case USBTMC488_IOCTL_WAIT_SRQ:
+		retval = usbtmc488_ioctl_wait_srq(file_data,
+						  (__u32 __user *)arg);
+		break;
+
 	case USBTMC_IOCTL_CANCEL_IO:
 		retval = usbtmc_ioctl_cancel_io(file_data);
 		break;