diff options
| -rw-r--r-- | drivers/usb/usb-skeleton.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c index 5ffa3e24685..768fda9064e 100644 --- a/drivers/usb/usb-skeleton.c +++ b/drivers/usb/usb-skeleton.c @@ -399,9 +399,16 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou goto exit; /* limit the number of URBs in flight to stop a user from using up all RAM */ - if (down_interruptible(&dev->limit_sem)) { - retval = -ERESTARTSYS; - goto exit; + if (!file->f_flags & O_NONBLOCK) { + if (down_interruptible(&dev->limit_sem)) { + retval = -ERESTARTSYS; + goto exit; + } + } else { + if (down_trylock(&dev->limit_sem)) { + retval = -EAGAIN; + goto exit; + } } spin_lock_irq(&dev->err_lock); |