usbip: fix off-by-one frame number calculation

vgadget_get_frame returns a frame number from 0 to 2046, which
may require an expensive division operation to wrap at one lower
than the usual number.

I can't see any reason for this, and all other drivers wrap at
a power-of-two number. My best explanation is that it was a simple
typo, so I'm changing the % modulo operator into a cheaper bitmask
that the other drivers use, to make it wrap after 0x7ff rather than
before it.

Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Krzysztof Opasiak <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions