[PATCH 06/13] Handle a non blocking read without blocking

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux