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[RFC,v2,15/21] media: Add poll support

Message ID 1464108451-28142-16-git-send-email-sakari.ailus@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sakari Ailus May 24, 2016, 4:47 p.m. UTC 
Implement poll for events. POLLPRI is used to notify users on incoming
events.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/media-device.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
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Patch

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 2ff8b29..25f7aea 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -1041,6 +1041,33 @@  static long media_device_ioctl(struct file *filp, unsigned int cmd,
 		ioctl_info, ARRAY_SIZE(ioctl_info));
 }
 
+unsigned int media_device_poll(struct file *filp, struct poll_table_struct *wait)
+{
+	struct media_device_fh *fh = media_device_fh(filp);
+	struct media_device *mdev = to_media_device(fh->fh.devnode);
+	unsigned int poll_events = poll_requested_events(wait);
+	int ret = 0;
+
+	if (poll_events & (POLLIN | POLLOUT))
+		return POLLERR;
+
+	if (poll_events & POLLPRI) {
+		unsigned long flags;
+		bool empty;
+
+		spin_lock_irqsave(&mdev->req_lock, flags);
+		empty = list_empty(&fh->kevents.head);
+		spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+		if (empty)
+			poll_wait(filp, &fh->kevents.wait, wait);
+		else
+			ret |= POLLPRI;
+	}
+
+	return ret;
+}
+
 #ifdef CONFIG_COMPAT
 
 struct media_links_enum32 {
@@ -1095,6 +1122,7 @@  static const struct media_file_operations media_device_fops = {
 	.owner = THIS_MODULE,
 	.open = media_device_open,
 	.ioctl = media_device_ioctl,
+	.poll = media_device_poll,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = media_device_compat_ioctl,
 #endif /* CONFIG_COMPAT */