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Diffstat (limited to 'drivers/iio/industrialio-event.c')
-rw-r--r--drivers/iio/industrialio-event.c100
1 files changed, 47 insertions, 53 deletions
diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
index c9c1419fe6e..ea6e06b9c7d 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;
- return ret ? ret : copied;
+ } while (copied == 0);
+
+ 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;
}
@@ -366,32 +364,31 @@ 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 +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";
@@ -440,10 +438,8 @@ 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 +485,6 @@ 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;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-30 23:22:24 +0000