diff options
| -rw-r--r-- | drivers/iio/industrialio-event.c | 83 |
1 files changed, 41 insertions, 42 deletions
diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c index 2e6f8e026fab..ea6e06b9c7d4 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); + + 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; -error_unlock: - spin_unlock_irq(&ev_int->wait.lock); + } 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; } @@ -424,6 +422,7 @@ 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"; |