| From 33b8807a6fe10d0e675e0704444373a6fad93188 Mon Sep 17 00:00:00 2001 |
| From: Johan Hovold <johan@kernel.org> |
| Date: Thu, 26 Jan 2017 12:37:32 +0100 |
| Subject: staging: greybus: loopback: fix broken udelay |
| |
| From: Johan Hovold <johan@kernel.org> |
| |
| commit 33b8807a6fe10d0e675e0704444373a6fad93188 upstream. |
| |
| The loopback driver allows the user to set a minimum delay of up to one |
| second to be inserted between test iterations (i.e. request |
| submissions). The delay is currently specified in microseconds and is |
| implemented using udelay. |
| |
| Busy looping for long periods is not just anti-social; udelay must not |
| be used for delays longer than a few milliseconds due to the risk of |
| integer overflow. |
| |
| Replace the broken udelay with a usleep_range with a 100 us range for |
| short delays (< 20 ms) and otherwise revert to using msleep. |
| |
| Fixes: b36f04fa9417 ("greybus: loopback: Convert thread delay to microseconds") |
| Signed-off-by: Johan Hovold <johan@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/staging/greybus/loopback.c | 9 +++++++-- |
| 1 file changed, 7 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/staging/greybus/loopback.c |
| +++ b/drivers/staging/greybus/loopback.c |
| @@ -1051,8 +1051,13 @@ static int gb_loopback_fn(void *data) |
| gb_loopback_calculate_stats(gb, !!error); |
| } |
| gb->send_count++; |
| - if (us_wait) |
| - udelay(us_wait); |
| + |
| + if (us_wait) { |
| + if (us_wait < 20000) |
| + usleep_range(us_wait, us_wait + 100); |
| + else |
| + msleep(us_wait / 1000); |
| + } |
| } |
| |
| gb_pm_runtime_put_autosuspend(bundle); |