USB: xhci: Remove buggy assignment in next_trb()

The code to increment the TRB pointer has a slight ambiguity that could
lead to a bug on different compilers.  The ANSI C specification does not
specify the precedence of the assignment operator over the postfix
operator.  gcc 4.4 produced the correct code (increment the pointer and
assign the value), but a MIPS compiler that one of John's clients used
assigned the old (unincremented) value.

Remove the unnecessary assignment to make all compilers produce the
correct assembly.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index bc3f4f427065901059737ca960bd03d0fa75a8fc..2f19f3a817c245886a8050e965f79798844fcb24 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -131,7 +131,7 @@ static void next_trb(struct xhci_hcd *xhci,
                *seg = (*seg)->next;
                *trb = ((*seg)->trbs);
        } else {
-               *trb = (*trb)++;
+               (*trb)++;
        }
 }