On Monday 24 September 2012, Chunhe Lan wrote:
> OK. As you have mentioned, it would been modified to such:
>
> static inline void mmc_delay(unsigned int ms)
> {
> if (ms < 1000 / HZ) {
> cond_resched();
> msleep(ms);
> } else {
> msleep(ms);
> }
> }
This version would be rather broken, because it compares times
in two different units (ms and jiffies), and because it
does a cond_resched() directly before an msleep: both of which
end up calling schedule() and being away for some time,
cond_resched() for an unknown time, and msleep for a minimum
time on top of that.
> OR such:
>
> static inline void mmc_delay(unsigned int ms)
> {
> msleep(ms);
> }
That would be my preferred choice, unless someone has specific issues with this.
> OR other code?
Well, in principle, you could implement something like
static inline void mmc_delay(unsigned int ms)
{
ktime_t end = ktime_add_us(ktime_get(), ms * 1000);
while (1) {
s64 remaining;
cond_resched();
remaining = ktime_to_us(ktime_sub(end, ktime_get()));
if (remaining < 0)
break;
udelay(min_t(u32, remaining, 100));
}
}
Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
