Use the waitqueue lock to protect the event queue instead of a custom mutex. This has the advantage that we can call the waitqueue operations with the lock held, which simplifies the code flow a bit.
Signed-off-by: Lars-Peter Clausen <[email protected]> Acked-by: Jonathan Cameron <[email protected]> -- Changes since v1: * Also remove documentation for event_list_lock --- drivers/staging/iio/industrialio-event.c | 44 ++++++++++++----------------- 1 files changed, 18 insertions(+), 26 deletions(-) diff --git a/drivers/staging/iio/industrialio-event.c b/drivers/staging/iio/industrialio-event.c index 335b615..2e7cf88 100644 --- a/drivers/staging/iio/industrialio-event.c +++ b/drivers/staging/iio/industrialio-event.c @@ -27,7 +27,6 @@ /** * struct iio_event_interface - chrdev interface for an event line * @wait: wait queue to allow blocking reads of events - * @event_list_lock: mutex to protect the list of detected events * @det_events: list of detected events * @dev_attr_list: list of event interface sysfs attribute * @flags: file operations related flags including busy flag. @@ -35,7 +34,6 @@ */ struct iio_event_interface { wait_queue_head_t wait; - struct mutex event_list_lock; DECLARE_KFIFO(det_events, struct iio_event_data, 16); struct list_head dev_attr_list; @@ -50,19 +48,17 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) int copied; /* Does anyone care? */ - mutex_lock(&ev_int->event_list_lock); + spin_lock(&ev_int->wait.lock); if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { ev.id = ev_code; ev.timestamp = timestamp; copied = kfifo_put(&ev_int->det_events, &ev); - - mutex_unlock(&ev_int->event_list_lock); if (copied != 0) - wake_up_interruptible(&ev_int->wait); - } else - mutex_unlock(&ev_int->event_list_lock); + wake_up_locked(&ev_int->wait); + } + spin_unlock(&ev_int->wait.lock); return 0; } @@ -80,28 +76,25 @@ static ssize_t iio_event_chrdev_read(struct file *filep, if (count < sizeof(struct iio_event_data)) return -EINVAL; - mutex_lock(&ev_int->event_list_lock); + spin_lock(&ev_int->wait.lock); if (kfifo_is_empty(&ev_int->det_events)) { if (filep->f_flags & O_NONBLOCK) { ret = -EAGAIN; - goto error_mutex_unlock; + goto error_unlock; } - mutex_unlock(&ev_int->event_list_lock); /* Blocking on device; waiting for something to be there */ - ret = wait_event_interruptible(ev_int->wait, + ret = wait_event_interruptible_locked(ev_int->wait, !kfifo_is_empty(&ev_int->det_events)); if (ret) - goto error_ret; + goto error_unlock; /* Single access device so no one else can get the data */ - mutex_lock(&ev_int->event_list_lock); } - mutex_unlock(&ev_int->event_list_lock); ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); -error_mutex_unlock: - mutex_unlock(&ev_int->event_list_lock); -error_ret: +error_unlock: + spin_unlock(&ev_int->wait.lock); + return ret ? ret : copied; } @@ -109,7 +102,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep) { struct iio_event_interface *ev_int = filep->private_data; - mutex_lock(&ev_int->event_list_lock); + spin_lock(&ev_int->wait.lock); clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); /* * In order to maintain a clean state for reopening, @@ -117,7 +110,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep) * any new __iio_push_event calls running. */ kfifo_reset_out(&ev_int->det_events); - mutex_unlock(&ev_int->event_list_lock); + spin_unlock(&ev_int->wait.lock); return 0; } @@ -137,18 +130,18 @@ int iio_event_getfd(struct iio_dev *indio_dev) if (ev_int == NULL) return -ENODEV; - mutex_lock(&ev_int->event_list_lock); + spin_lock(&ev_int->wait.lock); if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { - mutex_unlock(&ev_int->event_list_lock); + spin_unlock(&ev_int->wait.lock); return -EBUSY; } - mutex_unlock(&ev_int->event_list_lock); + spin_unlock(&ev_int->wait.lock); fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, ev_int, O_RDONLY); if (fd < 0) { - mutex_lock(&ev_int->event_list_lock); + spin_lock(&ev_int->wait.lock); clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); - mutex_unlock(&ev_int->event_list_lock); + spin_unlock(&ev_int->wait.lock); } return fd; } @@ -360,7 +353,6 @@ static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) static void iio_setup_ev_int(struct iio_event_interface *ev_int) { - mutex_init(&ev_int->event_list_lock); INIT_KFIFO(ev_int->det_events); init_waitqueue_head(&ev_int->wait); } -- 1.7.8.3 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
