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Commit 06cd928b authored by Michal Nazarewicz's avatar Michal Nazarewicz Committed by Felipe Balbi
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usb: gadget: f_midi: fix in_last_port looping logic 



In general case, all of midi->in_port pointers may be non-NULL which
implies that the ‘if (\!port)’ condition will never execute thus never
zeroing midi->in_last_port.  Fix by rewriting the loop such that the
field is set to zero if \!port or end of loop has been reached.

Signed-off-by: default avatarMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: default avatarFelipe Balbi <balbi@kernel.org>
parent 9a71eb56

drivers/usb/gadget/function/f_midi.c

+7 −19
Original line number Original line Diff line number Diff line
@@ -534,6 +534,7 @@ static void f_midi_drop_out_substreams(struct f_midi *midi) 
static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)

static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)

{

{

	struct usb_request *req = NULL;

	struct usb_request *req = NULL;

	struct gmidi_in_port *port;

	unsigned int len, i;

	unsigned int len, i;

	bool active = false;

	bool active = false;

	int err;

	int err;
@@ -557,16 +558,9 @@ static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep) 
	if (req->length > 0)

	if (req->length > 0)

		return 0;

		return 0;





	for (i = midi->in_last_port; i < MAX_PORTS; i++) {

	i = midi->in_last_port;

		struct gmidi_in_port *port = midi->in_port[i];

	for (; i < MAX_PORTS && (port = midi->in_port[i]); ++i) {

		struct snd_rawmidi_substream *substream = midi->in_substream[i];

		struct snd_rawmidi_substream *substream = midi->in_substream[i];



		if (!port) {

			/* Reset counter when we reach the last available port */

			midi->in_last_port = 0;

			break;

		}



		if (!port->active || !substream)

		if (!port->active || !substream)

			continue;

			continue;
@@ -581,20 +575,13 @@ static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep) 
		}

		}





		active = !!port->active;

		active = !!port->active;

		/*

		if (active)

		 * Check if last port is still active, which means that there is

		 * still data on that substream but this current request run out

		 * of space.

		 */

		if (active) {

			midi->in_last_port = i;

			/* There is no need to re-iterate though midi ports. */

			break;

			break;

	}

	}

	}

	midi->in_last_port = active ? i : 0;





	if (req->length <= 0)

	if (req->length <= 0)

		return active;

		goto done;





	err = usb_ep_queue(ep, req, GFP_ATOMIC);

	err = usb_ep_queue(ep, req, GFP_ATOMIC);

	if (err < 0) {

	if (err < 0) {
@@ -607,6 +594,7 @@ static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep) 
		kfifo_put(&midi->in_req_fifo, req);

		kfifo_put(&midi->in_req_fifo, req);

	}

	}





done:

	return active;

	return active;

}

}