Sometimes it's necessary to poll with long sleeps, and the accuracy of usleep_range() is overkill. Use the flexible sleep helper fsleep() for sleeping in the read_poll_timeout() family of macros to automatically choose the appropriate method of waiting.
Functionally there are a few consequences for existing users: - 10 us and shorter sleeps will use usleep() instead of usleep_range(). Presumably this will not be an issue. - When it leads to a slack of less than 25%, msleep() will be used instead of usleep_range(). Presumably this will not be an issue, given the sleeps will be longer in this case. - Otherwise, the usleep_range() slack gets switched from the begin of the range to the end of the range, i.e. [sleep/2+1..sleep] -> [sleep..sleep+sleep/2]. In theory, this could be an issue in some cases, but difficult to determine before this hits the real world. Signed-off-by: Jani Nikula <[email protected]> --- Not really sure who to Cc, given MAINTAINERS doesn't match this. Adding some past committers. Cc: Thomas Gleixner <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: [email protected] --- include/linux/iopoll.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h index 91324c331a4b..359ff5ab95de 100644 --- a/include/linux/iopoll.h +++ b/include/linux/iopoll.h @@ -20,7 +20,7 @@ * @val: Variable to read the value into * @cond: Break condition (usually involving @val) * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please - * read usleep_range() function description for details and + * read fsleep() function description for details and * limitations. * @timeout_us: Timeout in us, 0 means never timeout * @sleep_before_read: if it is true, sleep @sleep_us before read. @@ -41,7 +41,7 @@ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ might_sleep_if((__sleep_us) != 0); \ if (sleep_before_read && __sleep_us) \ - usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ + fsleep(__sleep_us); \ for (;;) { \ (val) = op(args); \ if (cond) \ @@ -52,7 +52,7 @@ break; \ } \ if (__sleep_us) \ - usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ + fsleep(__sleep_us); \ cpu_relax(); \ } \ (cond) ? 0 : -ETIMEDOUT; \ @@ -120,7 +120,7 @@ * @val: Variable to read the value into * @cond: Break condition (usually involving @val) * @sleep_us: Maximum time to sleep between reads in us (0 tight-loops). Please - * read usleep_range() function description for details and + * read fsleep() function description for details and * limitations. * @timeout_us: Timeout in us, 0 means never timeout * -- 2.39.5
