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 <aksgarg1989@xxxxxxxxx>
> ---
> 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 majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
