On Thu, May 07, 2020 at 06:25:21PM +0800, Jia-Ju Bai wrote: > In ttusb_dec_handle_irq(), buffer[4] is continuously read from memory > three times, without being modified. > To reduce the number of memory reads, buffer[4] is first assigned to a > local variable index, and then index is used to replace buffer[4]. > > Signed-off-by: Jia-Ju Bai <[email protected]> > --- > drivers/media/usb/ttusb-dec/ttusb_dec.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/usb/ttusb-dec/ttusb_dec.c > b/drivers/media/usb/ttusb-dec/ttusb_dec.c > index 3198f9624b7c..8543c552515b 100644 > --- a/drivers/media/usb/ttusb-dec/ttusb_dec.c > +++ b/drivers/media/usb/ttusb-dec/ttusb_dec.c > @@ -250,6 +250,7 @@ static void ttusb_dec_handle_irq( struct urb *urb) > struct ttusb_dec *dec = urb->context; > char *buffer = dec->irq_buffer; > int retval; > + int index = buffer[4]; > > switch(urb->status) { > case 0: /*success*/ > @@ -281,11 +282,11 @@ static void ttusb_dec_handle_irq( struct urb *urb) > * this should/could be added later ... > * for now lets report each signal as a key down and up > */ > - if (buffer[4] - 1 < ARRAY_SIZE(rc_keys)) { > - dprintk("%s:rc signal:%d\n", __func__, buffer[4]); > - input_report_key(dec->rc_input_dev, rc_keys[buffer[4] - > 1], 1); > + if (index - 1 < ARRAY_SIZE(rc_keys)) { > + dprintk("%s:rc signal:%d\n", __func__, index); > + input_report_key(dec->rc_input_dev, rc_keys[index - 1], > 1); > input_sync(dec->rc_input_dev); > - input_report_key(dec->rc_input_dev, rc_keys[buffer[4] - > 1], 0); > + input_report_key(dec->rc_input_dev, rc_keys[index - 1], > 0); > input_sync(dec->rc_input_dev); > } > } > -- > 2.17.1 >
Reviewed-by: Greg Kroah-Hartman <[email protected]>
