2023-11-18 15:55:48

by Yury Norov

Subject: [PATCH 21/34] usb: cdc-acm: optimize acm_softint()

acm_softint(), uses for-loop to traverse urbs_in_error_delay bitmap
bit by bit to find and clear set bits.

We can do it better by using for_each_test_and_clear_bit(), because it
doesn't test already clear bits.

Signed-off-by: Yury Norov <[email protected]>
---
drivers/usb/class/cdc-acm.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index a1f4e1ead97f..8664b63050b0 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -613,9 +613,8 @@ static void acm_softint(struct work_struct *work)
}

if (test_and_clear_bit(ACM_ERROR_DELAY, &acm->flags)) {
- for (i = 0; i < acm->rx_buflimit; i++)
- if (test_and_clear_bit(i, &acm->urbs_in_error_delay))
- acm_submit_read_urb(acm, i, GFP_KERNEL);
+ for_each_test_and_clear_bit(i, &acm->urbs_in_error_delay, acm->rx_buflimit)
+ acm_submit_read_urb(acm, i, GFP_KERNEL);
}

if (test_and_clear_bit(EVENT_TTY_WAKEUP, &acm->flags))
--
2.39.2

2023-11-20 11:39:48

by Oliver Neukum

Subject: Re: [PATCH 21/34] usb: cdc-acm: optimize acm_softint()

On 18.11.23 16:50, Yury Norov wrote:
> acm_softint(), uses for-loop to traverse urbs_in_error_delay bitmap
> bit by bit to find and clear set bits.
>
> We can do it better by using for_each_test_and_clear_bit(), because it
> doesn't test already clear bits.
>
> Signed-off-by: Yury Norov <[email protected]>
Acked-by: Oliver Neukum <[email protected]>