usb: gadget: dummy: fix nonsensical comparisons

commit 7661ca09b2ff98f48693f431bb01fed62830e433 upstream.

gcc-8 points out two comparisons that are clearly bogus
and almost certainly not what the author intended to write:

drivers/usb/gadget/udc/dummy_hcd.c: In function 'set_link_state_by_speed':
drivers/usb/gadget/udc/dummy_hcd.c:379:31: error: bitwise comparison always evaluates to false [-Werror=tautological-compare]
         USB_PORT_STAT_ENABLE) == 1 &&
                               ^~
drivers/usb/gadget/udc/dummy_hcd.c:381:25: error: bitwise comparison always evaluates to false [-Werror=tautological-compare]
      USB_SS_PORT_LS_U0) == 1 &&
                         ^~

I looked at the code for a bit and came up with a change that makes
it look like what the author probably meant here. This makes it
look reasonable to me and to gcc, shutting up the warning.

It does of course change behavior as the two conditions are actually
evaluated rather than being hardcoded to false, and I have made no
attempt at verifying that the changed logic makes sense in the context
of a USB HCD, so that part needs to be reviewed carefully.

Fixes: 1cd8fd2887e1 ("usb: gadget: dummy_hcd: add SuperSpeed support")
Cc: Tatyana Brokhman <tlinder@codeaurora.org>
Cc: Felipe Balbi <balbi@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index ff4d6cac7ac0cde492a2a4355b6005ed9affb04b..ab89fa3b4118bc17a01d7680b29ae900128b2277 100644 (file)
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -379,11 +379,10 @@ static void set_link_state_by_speed(struct dummy_hcd *dum_hcd)
                             USB_PORT_STAT_CONNECTION) == 0)
                                dum_hcd->port_status |=
                                        (USB_PORT_STAT_C_CONNECTION << 16);
-                       if ((dum_hcd->port_status &
-                            USB_PORT_STAT_ENABLE) == 1 &&
-                               (dum_hcd->port_status &
-                                USB_SS_PORT_LS_U0) == 1 &&
-                               dum_hcd->rh_state != DUMMY_RH_SUSPENDED)
+                       if ((dum_hcd->port_status & USB_PORT_STAT_ENABLE) &&
+                           (dum_hcd->port_status &
+                            USB_PORT_STAT_LINK_STATE) == USB_SS_PORT_LS_U0 &&
+                           dum_hcd->rh_state != DUMMY_RH_SUSPENDED)
                                dum_hcd->active = 1;
                }
        } else {