Re: [PATCH v2 0/5] usb: gadget: u_serial: Fix and cleanup

[Ladislav Michl <ladis@linux-mips.org>]

Hi Michał,

On Sun, Jul 14, 2019 at 12:04:26PM +0200, Michał Mirosław wrote:
> On Sat, Jul 13, 2019 at 11:08:53PM +0200, Ladislav Michl wrote:
> > Following patchset makes console work (patch 1 and 4) for an AT91SAM9G20
> > board connected to xhci_hcd and does some cleanup.
> > Tested with "console=ttyS0,115200n8 console=ttyGS0" on kernel command line
> > and following inittab:
> > console::respawn:/sbin/getty -L 115200 ttyS0 vt100
> > console::respawn:/sbin/getty -L 115200 ttyGS0 vt100
> > 
> > However there is an issue remaining:
> > Disconnect triggers WARN_ON in gs_close:
> [...]
> 
> Hi,
> 
> Can you try a patchset I sent some time ago [1] if it fixes your case?

your "usb: gadget: u_serial: add missing port entry locking" and
"usb: gadget: u_serial: reimplement console support" fixes every single
problem I had with the driver (including that WARN_ON on gs_close),
except starving console write.
Fortunately my patch "usb: gadget: u_serial: Fix starving write"
applies on top of your first two patches.

So here's my
Tested-by: Ladislav Michl <ladis@linux-mips.org>
and also one nit for your second patch (there are people running cocci scripts,
so save them some time ;-)):
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -931,8 +931,8 @@ static void gs_console_complete_out(struct usb_ep *ep, struct usb_request *req)
 static void __gs_console_push(struct gs_console *cons)
 {
 	struct usb_request *req = cons->req;
-	struct usb_ep *ep = cons->console.data;
-	size_t size = 0;
+	struct usb_ep *ep;
+	size_t size;
 
 	if (!req)
 		return;	/* disconnected */
@@ -940,6 +940,7 @@ static void __gs_console_push(struct gs_console *cons)
 	if (req->length)
 		return;	/* busy */
 
+	ep = cons->console.data;
 	size = kfifo_out(&cons->buf, req->buf, ep->maxpacket);
 	if (!size)
 		return;

I'm dropping all my patches except the fourth one in favour of your solution
as it is clearly superior. Care to resend it possibly with above fix and
said fourth patch as a single serie?

Thank you,
	ladis