From: Oliver Neukum <oliver@xxxxxxxxxx> Non blocking IO is supported in the read path of usb-skeleton. This is done by just not blocking. As support for handling signals without stopping IO is already there, it can be used for O_NONBLOCK, too. Signed-off-by: Oliver Neukum <oliver@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx> --- drivers/usb/usb-skeleton.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c index 768fda9..ef8c877 100644 --- a/drivers/usb/usb-skeleton.c +++ b/drivers/usb/usb-skeleton.c @@ -268,6 +268,11 @@ retry: spin_unlock_irq(&dev->err_lock); if (ongoing_io) { + /* nonblocking IO shall not wait */ + if (file->f_flags & O_NONBLOCK) { + rv = -EAGAIN; + goto exit; + } /* * IO may take forever * hence wait in an interruptible state @@ -351,8 +356,9 @@ retry: rv = skel_do_read_io(dev, count); if (rv < 0) goto exit; - else + else if (!file->f_flags & O_NONBLOCK) goto retry; + rv = -EAGAIN; } exit: mutex_unlock(&dev->io_mutex); -- 1.6.4.2 -- 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