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Commit 49631ca7 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: gadgetfs AIO tweaks 



This patch (as837) fixes several mistakes in the AIO interface of the
gadgetfs driver:

	The ki_retry method is not supposed to do a put on the kiocb.
	The extra call to aio_put_req() causes memory corruption.
	(Note: This call was removed before, by patch as691, and then
	mysteriously re-introduced later.)

	Even if a read transfer is cancelled, we can and should send
	to the user all the data that did manage to get transferred.

	Testing for AIO cancellation in the I/O completion handler
	is both racy and (now) unnecessary.  aio_complete() does its
	own checking, in a safe manner.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent ce46794f

drivers/usb/gadget/inode.c

+7 −9
Original line number Diff line number Diff line
@@ -576,7 +576,6 @@ static ssize_t ep_aio_read_retry(struct kiocb *iocb) 
	}

	kfree(priv->buf);

	kfree(priv);

	aio_put_req(iocb);

	return len;

}
@@ -590,18 +589,17 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req) 
	spin_lock(&epdata->dev->lock);

	priv->req = NULL;

	priv->epdata = NULL;

	if (priv->iv == NULL

			|| unlikely(req->actual == 0)

			|| unlikely(kiocbIsCancelled(iocb))) {



	/* if this was a write or a read returning no data then we

	 * don't need to copy anything to userspace, so we can

	 * complete the aio request immediately.

	 */

	if (priv->iv == NULL || unlikely(req->actual == 0)) {

		kfree(req->buf);

		kfree(priv);

		iocb->private = NULL;

		/* aio_complete() reports bytes-transferred _and_ faults */

		if (unlikely(kiocbIsCancelled(iocb)))

			aio_put_req(iocb);

		else

			aio_complete(iocb,

				req->actual ? req->actual : req->status,

		aio_complete(iocb, req->actual ? req->actual : req->status,

				req->status);

	} else {

		/* retry() won't report both; so we hide some faults */