From: Stefani Seibold <stefani@xxxxxxxxxxx>
Signed-off-by: Stefani Seibold <stefani@xxxxxxxxxxx>
---
drivers/usb/usb-skeleton.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 2ca2530..e4cb88a 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -225,9 +225,14 @@ static ssize_t skel_read(struct file *file, char *buffer, size_t count,
return 0;
/* no concurrent readers */
- retval = mutex_lock_interruptible(&dev->io_mutex);
- if (retval < 0)
- return retval;
+ if (file->f_flags & O_NONBLOCK) {
+ if (!mutex_trylock(&dev->io_mutex))
+ return -EAGAIN;
+ } else {
+ retval = mutex_lock_interruptible(&dev->io_mutex);
+ if (retval < 0)
+ return retval;
+ }
if (!dev->interface) { /* disconnect() was called */
retval = -ENODEV;
--
1.7.8.6
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