[PATCH] drm: Honour O_NONBLOCK on the device for reading events

[Chris Wilson]

Otherwise drmHandleEvent will block if accidentally read too often...

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Phillip Haddad <phillip.haddad at gmail.com>
---
 drivers/gpu/drm/drm_fops.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 2ec7d48..279aa95 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -617,6 +617,9 @@ ssize_t drm_read(struct file *filp, char __user *buffer,
 	size_t total;
 	ssize_t ret;
 
+	if (filp->f_flags & O_NONBLOCK && list_empty(&file_priv->event_list))
+		return -EAGAIN;
+
 	ret = wait_event_interruptible(file_priv->event_wait,
 				       !list_empty(&file_priv->event_list));
 	if (ret < 0)
-- 
1.7.5.3