Messages in this thread Patch in this message | | | From | stefani@seibold ... | Subject | [PATCH 08/11] Handle a non blocking read without blocking | Date | Wed, 6 Jun 2012 18:27:09 +0200 |
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From: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net> --- 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 cab16e2..46c1bbb 100644 --- a/drivers/usb/usb-skeleton.c +++ b/drivers/usb/usb-skeleton.c @@ -241,9 +241,14 @@ 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->connected) { /* disconnect() was called */ retval = -ENODEV; -- 1.7.8.6
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