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Commit 79819986 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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USB: make usb-skeleton honor O_NONBLOCK in write path 



usb:usb-skeleton: honor O_NONBLOCK in write path

nonblocking writes are allowed by using down_trylock if necessary
to reserve an URB

Signed-off-by: default avatarOliver Neukum <oliver@neukum.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e7389cc9

drivers/usb/usb-skeleton.c

+10 −3
Original line number Diff line number Diff line
@@ -399,10 +399,17 @@ 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 (!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);

	if ((retval = dev->errors) < 0) {