On Thu, Jul 09, 2015 at 06:41:01AM -0700, Anshul Garg wrote: > Use for_each_set_bit to check for set bits in bitmap > as it is more efficient and compact. > Also use bitwise and instead of expensive % > operation while fetching next event.
It is not expensive if we are using a constant that is carefully selected (and it is). > > Signed-off-by: Anshul Garg <[email protected]> > --- > drivers/input/misc/uinput.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c > index 421e29e..a3c15ad 100644 > --- a/drivers/input/misc/uinput.c > +++ b/drivers/input/misc/uinput.c > @@ -319,11 +319,8 @@ static int uinput_validate_absbits(struct input_dev *dev) > /* > * Check if absmin/absmax/absfuzz/absflat are sane. > */ > - > - for (cnt = 0; cnt < ABS_CNT; cnt++) { > + for_each_set_bit(cnt, dev->absbit, ABS_CNT) { > int min, max; > - if (!test_bit(cnt, dev->absbit)) > - continue; > > min = input_abs_get_min(dev, cnt); > max = input_abs_get_max(dev, cnt); > @@ -415,8 +412,8 @@ static int uinput_setup_device(struct uinput_device *udev, > dev->id.vendor = user_dev->id.vendor; > dev->id.product = user_dev->id.product; > dev->id.version = user_dev->id.version; > - > - for (i = 0; i < ABS_CNT; i++) { > + > + for_each_set_bit(i, dev->absbit, ABS_CNT) { > input_abs_set_max(dev, i, user_dev->absmax[i]); > input_abs_set_min(dev, i, user_dev->absmin[i]); > input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]); > @@ -493,7 +490,7 @@ static bool uinput_fetch_next_event(struct uinput_device > *udev, > have_event = udev->head != udev->tail; > if (have_event) { > *event = udev->buff[udev->tail]; > - udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE; > + udev->tail &= UINPUT_BUFFER_SIZE - 1; What is this exactly? And how did you test it? This chunk dropped form the patch. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
