USB: usbdevfs: restore warning for nonsensical flags

Quoted 18 lines · Greg KH

Quoted 17 lines · Oliver Neukum

If we filter flags before they reach the core we need to generate our own warnings.

Signed-off-by Oliver Neukum <[email protected]>

Fixes 0cb54a3e47cb ("USB: debugging code shouldn't alter control flow")

---
 drivers/usb/core/devio.c | 5 +++++
 1 file changed, 5 insertions(+)

drivers/usb/core/devio.c +0 -0

index 263dd2f309fb..244417d0dfd1 100644
@@ -1697,6 +1697,11 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
 		u |= URB_NO_INTERRUPT;
 	as->urb->transfer_flags = u;
 

Quoted 8 lines

drivers/usb/core/devio.c static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb · line 1703

Quoted 4 lines

drivers/usb/core/devio.c +4 -0

+	if (!allow_short && uurb->flags & USBDEVFS_URB_SHORT_NOT_OK)
+		dev_warn(&ps->dev->dev, "Requested nonsensical USBDEVFS_URB_SHORT_NOT_OK.\n");
+	if (!allow_zero && uurb->flags & USBDEVFS_URB_ZERO_PACKET)
+		dev_warn(&ps->dev->dev, "Requested nonsensical USBDEVFS_URB_ZERO_PACKET.\n");

We should not make it trivial for userspace to spam the kernel log if at all possible. Returning an error is probably the better thing to do here, not just silently fix it up or ignore it.

That means a change in the API in a way that makes orking systems fail.

Do you want an extra version for stable?