From: Ville Syrjälä <[email protected]> Currently poll_timeout_us() evaluates 'cond' twice at the end of the success case. This not desirable in case 'cond' itself is expensive.
Avoid the double evaluation by tracking the return value in a variable. Need to use a triple undescore '___ret' name to avoid a conflict with an existing double undescore '__ret' variable in the regmap code. Cc: Jani Nikula <[email protected]> Cc: Lucas De Marchi <[email protected]> Cc: Dibin Moolakadan Subrahmanian <[email protected]> Cc: Imre Deak <[email protected]> Cc: David Laight <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Matt Wagantall <[email protected]> Cc: Dejin Zheng <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Ville Syrjälä <[email protected]> --- include/linux/iopoll.h | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h index 0d8186d3df03..69296e6adbf3 100644 --- a/include/linux/iopoll.h +++ b/include/linux/iopoll.h @@ -36,23 +36,30 @@ u64 __timeout_us = (timeout_us); \ unsigned long __sleep_us = (sleep_us); \ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ + int ___ret; \ might_sleep_if((__sleep_us) != 0); \ if ((sleep_before_op) && __sleep_us) \ usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ for (;;) { \ op; \ - if (cond) \ + if (cond) { \ + ___ret = 0; \ break; \ + } \ if (__timeout_us && \ ktime_compare(ktime_get(), __timeout) > 0) { \ op; \ + if (cond) \ + ___ret = 0; \ + else \ + ___ret = -ETIMEDOUT; \ break; \ } \ if (__sleep_us) \ usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ cpu_relax(); \ } \ - (cond) ? 0 : -ETIMEDOUT; \ + ___ret; \ }) /** @@ -83,6 +90,7 @@ s64 __left_ns = __timeout_us * NSEC_PER_USEC; \ unsigned long __delay_us = (delay_us); \ u64 __delay_ns = __delay_us * NSEC_PER_USEC; \ + int ___ret; \ if ((delay_before_op) && __delay_us) { \ udelay(__delay_us); \ if (__timeout_us) \ @@ -90,10 +98,16 @@ } \ for (;;) { \ op; \ - if (cond) \ + if (cond) { \ + ___ret = 0; \ break; \ + } \ if (__timeout_us && __left_ns < 0) { \ op; \ + if (cond) \ + ___ret = 0; \ + else \ + ___ret = -ETIMEDOUT; \ break; \ } \ if (__delay_us) { \ @@ -105,7 +119,7 @@ if (__timeout_us) \ __left_ns--; \ } \ - (cond) ? 0 : -ETIMEDOUT; \ + ___ret; \ }) /** -- 2.49.0
