USB: O_NONBLOCK in read path of skeleton (8cd01664) · Commits · 戴 / test

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@neukum.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/usb-skeleton.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -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);

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