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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: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
hifive-unleashed-5.1
Michal Nazarewicz 2016-01-18 18:30:15 +01:00 committed by Felipe Balbi
parent 9a71eb5634
commit 06cd928b0c
1 changed files with 7 additions and 19 deletions
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26
drivers/usb/gadget/function/f_midi.c
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@ -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)
{
struct usb_request *req = NULL;
struct gmidi_in_port *port;
unsigned int len, i;
bool active = false;
int err;
@ -557,16 +558,9 @@ static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)
if (req->length > 0)
return 0;
for (i = midi->in_last_port; i < MAX_PORTS; i++) {
struct gmidi_in_port *port = midi->in_port[i];
i = midi->in_last_port;
for (; i < MAX_PORTS && (port = midi->in_port[i]); ++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)
continue;
@ -581,20 +575,13 @@ static int f_midi_do_transmit(struct f_midi *midi, struct usb_ep *ep)
}
active = !!port->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. */
if (active)
break;
}
}
midi->in_last_port = active ? i : 0;
if (req->length <= 0)
return active;
goto done;
err = usb_ep_queue(ep, req, GFP_ATOMIC);
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);
}
done:
return active;
}