1 files changed, 57 insertions, 56 deletions

diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
index c9c1419fe6e..bfbf4d419f4 100644
--- a/drivers/iio/industrialio-event.c
+++ b/drivers/iio/industrialio-event.c
@@ -40,6 +40,7 @@ struct iio_event_interface {
 	struct list_head	dev_attr_list;
 	unsigned long		flags;
 	struct attribute_group	group;
+	struct mutex		read_lock;
 };
 
 /**
@@ -47,16 +48,17 @@ struct iio_event_interface {
  * @indio_dev:		IIO device structure
  * @ev_code:		What event
  * @timestamp:		When the event occurred
+ *
+ * Note: The caller must make sure that this function is not running
+ * concurrently for the same indio_dev more than once.
  **/
 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
 {
 	struct iio_event_interface *ev_int = indio_dev->event_interface;
 	struct iio_event_data ev;
-	unsigned long flags;
 	int copied;
 
 	/* Does anyone care? */
-	spin_lock_irqsave(&ev_int->wait.lock, flags);
 	if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
 
 		ev.id = ev_code;
@@ -64,9 +66,8 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
 
 		copied = kfifo_put(&ev_int->det_events, ev);
 		if (copied != 0)
-			wake_up_locked_poll(&ev_int->wait, POLLIN);
+			wake_up_poll(&ev_int->wait, POLLIN);
 	}
-	spin_unlock_irqrestore(&ev_int->wait.lock, flags);
 
 	return 0;
 }
@@ -87,10 +88,8 @@ static unsigned int iio_event_poll(struct file *filep,
 
 	poll_wait(filep, &ev_int->wait, wait);
 
-	spin_lock_irq(&ev_int->wait.lock);
 	if (!kfifo_is_empty(&ev_int->det_events))
 		events = POLLIN | POLLRDNORM;
-	spin_unlock_irq(&ev_int->wait.lock);
 
 	return events;
 }
@@ -111,31 +110,40 @@ static ssize_t iio_event_chrdev_read(struct file *filep,
 	if (count < sizeof(struct iio_event_data))
 		return -EINVAL;
 
-	spin_lock_irq(&ev_int->wait.lock);
-	if (kfifo_is_empty(&ev_int->det_events)) {
-		if (filep->f_flags & O_NONBLOCK) {
-			ret = -EAGAIN;
-			goto error_unlock;
-		}
-		/* Blocking on device; waiting for something to be there */
-		ret = wait_event_interruptible_locked_irq(ev_int->wait,
+	do {
+		if (kfifo_is_empty(&ev_int->det_events)) {
+			if (filep->f_flags & O_NONBLOCK)
+				return -EAGAIN;
+
+			ret = wait_event_interruptible(ev_int->wait,
 					!kfifo_is_empty(&ev_int->det_events) ||
 					indio_dev->info == NULL);
-		if (ret)
-			goto error_unlock;
-		if (indio_dev->info == NULL) {
-			ret = -ENODEV;
-			goto error_unlock;
+			if (ret)
+				return ret;
+			if (indio_dev->info == NULL)
+				return -ENODEV;
 		}
-		/* Single access device so no one else can get the data */
-	}
 
-	ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
+		if (mutex_lock_interruptible(&ev_int->read_lock))
+			return -ERESTARTSYS;
+		ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
+		mutex_unlock(&ev_int->read_lock);
 
-error_unlock:
-	spin_unlock_irq(&ev_int->wait.lock);
+		if (ret)
+			return ret;
+
+		/*
+		 * If we couldn't read anything from the fifo (a different
+		 * thread might have been faster) we either return -EAGAIN if
+		 * the file descriptor is non-blocking, otherwise we go back to
+		 * sleep and wait for more data to arrive.
+		 */
+		if (copied == 0 && (filep->f_flags & O_NONBLOCK))
+			return -EAGAIN;
+
+	} while (copied == 0);
 
-	return ret ? ret : copied;
+	return copied;
 }
 
 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
@@ -143,15 +151,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 	struct iio_dev *indio_dev = filep->private_data;
 	struct iio_event_interface *ev_int = indio_dev->event_interface;
 
-	spin_lock_irq(&ev_int->wait.lock);
-	__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
-	/*
-	 * In order to maintain a clean state for reopening,
-	 * clear out any awaiting events. The mask will prevent
-	 * any new __iio_push_event calls running.
-	 */
-	kfifo_reset_out(&ev_int->det_events);
-	spin_unlock_irq(&ev_int->wait.lock);
+	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
 
 	iio_device_put(indio_dev);
 
@@ -174,22 +174,20 @@ int iio_event_getfd(struct iio_dev *indio_dev)
 	if (ev_int == NULL)
 		return -ENODEV;
 
-	spin_lock_irq(&ev_int->wait.lock);
-	if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
-		spin_unlock_irq(&ev_int->wait.lock);
+	if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags))
 		return -EBUSY;
-	}
-	spin_unlock_irq(&ev_int->wait.lock);
+
 	iio_device_get(indio_dev);
 
 	fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
 				indio_dev, O_RDONLY | O_CLOEXEC);
 	if (fd < 0) {
-		spin_lock_irq(&ev_int->wait.lock);
-		__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
-		spin_unlock_irq(&ev_int->wait.lock);
+		clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
 		iio_device_put(indio_dev);
+	} else {
+		kfifo_reset_out(&ev_int->det_events);
 	}
+
 	return fd;
 }
 
@@ -272,7 +270,7 @@ static ssize_t iio_ev_value_show(struct device *dev,
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
-	int val, val2;
+	int val, val2, val_arr[2];
 	int ret;
 
 	ret = indio_dev->info->read_event_value(indio_dev,
@@ -281,7 +279,9 @@ static ssize_t iio_ev_value_show(struct device *dev,
 		&val, &val2);
 	if (ret < 0)
 		return ret;
-	return iio_format_value(buf, ret, val, val2);
+	val_arr[0] = val;
+	val_arr[1] = val2;
+	return iio_format_value(buf, ret, 2, val_arr);
 }
 
 static ssize_t iio_ev_value_store(struct device *dev,
@@ -323,7 +323,9 @@ static int iio_device_add_event(struct iio_dev *indio_dev,
 	char *postfix;
 	int ret;
 
-	for_each_set_bit(i, mask, sizeof(*mask)) {
+	for_each_set_bit(i, mask, sizeof(*mask)*8) {
+		if (i >= ARRAY_SIZE(iio_ev_info_text))
+			return -EINVAL;
 		postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
 				iio_ev_type_text[type], iio_ev_dir_text[dir],
 				iio_ev_info_text[i]);
@@ -343,6 +345,9 @@ static int iio_device_add_event(struct iio_dev *indio_dev,
 			&indio_dev->event_interface->dev_attr_list);
 		kfree(postfix);
 
+		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
+			continue;
+
 		if (ret)
 			return ret;
 
@@ -366,32 +371,31 @@ static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
 		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 			IIO_SEPARATE, &chan->event_spec[i].mask_separate);
 		if (ret < 0)
-			goto error_ret;
+			return ret;
 		attrcount += ret;
 
 		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 			IIO_SHARED_BY_TYPE,
 			&chan->event_spec[i].mask_shared_by_type);
 		if (ret < 0)
-			goto error_ret;
+			return ret;
 		attrcount += ret;
 
 		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 			IIO_SHARED_BY_DIR,
 			&chan->event_spec[i].mask_shared_by_dir);
 		if (ret < 0)
-			goto error_ret;
+			return ret;
 		attrcount += ret;
 
 		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 			IIO_SHARED_BY_ALL,
 			&chan->event_spec[i].mask_shared_by_all);
 		if (ret < 0)
-			goto error_ret;
+			return ret;
 		attrcount += ret;
 	}
 	ret = attrcount;
-error_ret:
 	return ret;
 }
 
@@ -425,6 +429,7 @@ static void iio_setup_ev_int(struct iio_event_interface *ev_int)
 {
 	INIT_KFIFO(ev_int->det_events);
 	init_waitqueue_head(&ev_int->wait);
+	mutex_init(&ev_int->read_lock);
 }
 
 static const char *iio_event_group_name = "events";
@@ -440,10 +445,8 @@ int iio_device_register_eventset(struct iio_dev *indio_dev)
 
 	indio_dev->event_interface =
 		kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
-	if (indio_dev->event_interface == NULL) {
-		ret = -ENOMEM;
-		goto error_ret;
-	}
+	if (indio_dev->event_interface == NULL)
+		return -ENOMEM;
 
 	INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
 
@@ -489,8 +492,6 @@ int iio_device_register_eventset(struct iio_dev *indio_dev)
 error_free_setup_event_lines:
 	iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
 	kfree(indio_dev->event_interface);
-error_ret:
-
 	return ret;
 }