On Friday 23 October 2015 17:24:59 WEN Pingbo wrote:
Using struct timeval will cause time overflow in 2038, replacing it with ktime_t. And we don't need to handle sec and nsec separately.
Since mlc->lcv_t is only interested in seconds, directly using time64_t here.
And monotonic time is better here, since the original driver don't care the wall time.
In addition, the original driver try to covert usec to jiffies manually in hilse_donode(). This is not a universal and safe way, using nsecs_to_jiffies() to fix that.
Signed-off-by: WEN Pingbo pingbo.wen@linaro.org
The changelog text looks good.
+++ b/drivers/input/serio/hil_mlc.c @@ -274,14 +274,12 @@ static int hilse_match(hil_mlc *mlc, int unused) /* An LCV used to prevent runaway loops, forces 5 second sleep when reset. */ static int hilse_init_lcv(hil_mlc *mlc, int unused) {
- struct timeval tv;
- time64_t now = ktime_get_seconds();
- do_gettimeofday(&tv);
- if (mlc->lcv && (tv.tv_sec - mlc->lcv_tv.tv_sec) < 5)
- if (mlc->lcv && (now - mlc->lcv_t) < 5) return -1;
- mlc->lcv_tv = tv;
- mlc->lcv_t = now; mlc->lcv = 0;
return 0;
This part looks good now, but as I commented in version 1, it should really be a separate patch rather than combined with the rest that is dealing with another use of timeval.
do_gettimeofday(&tv);tv.tv_usec += USEC_PER_SEC * (tv.tv_sec - mlc->instart.tv_sec);tv.tv_usec -= mlc->instart.tv_usec;if (tv.tv_usec >= mlc->intimeout) goto sched;tv.tv_usec = (mlc->intimeout - tv.tv_usec) * HZ / USEC_PER_SEC;if (!tv.tv_usec) goto sched;mod_timer(&hil_mlcs_kicker, jiffies + tv.tv_usec);
if (tmp.tv64 >= (mlc->intimeout * NSEC_PER_USEC))goto sched;tmp.tv64 = mlc->intimeout * NSEC_PER_USEC - tmp.tv64;if (tmp.tv64 < NSEC_PER_USEC)goto sched;mod_timer(&hil_mlcs_kicker,jiffies + nsecs_to_jiffies(tmp.tv64));
If I read this right, the code is executed one for each input event such as a keypress or mouse movement. In the latter case, doing nsecs_to_jiffies() here is actually a bit expensive, and I stil think it can be avoided by just using jiffies.
For the (tmp.tv64 < NSEC_PER_USEC) part, did you just do that because I said this, or did you actually prove that it is required? I'm still confused about what the driver is trying to achieve here.
diff --git a/drivers/input/serio/hp_sdc_mlc.c b/drivers/input/serio/hp_sdc_mlc.c index d50f067..0a27b89 100644 --- a/drivers/input/serio/hp_sdc_mlc.c +++ b/drivers/input/serio/hp_sdc_mlc.c @@ -149,7 +149,8 @@ static int hp_sdc_mlc_in(hil_mlc *mlc, suseconds_t timeout) /* Try to down the semaphore */ if (down_trylock(&mlc->isem)) {
struct timeval tv;
ktime_t tmp = ktime_sub(ktime_get(), mlc->instart);- if (priv->emtestmode) { mlc->ipacket[0] = HIL_ERR_INT | (mlc->opacket &
Maybe give the variable a more useful name than 'tmp'?
You could also remove the variable entirely if you slightly restructure the condition below.
@@ -160,9 +161,8 @@ static int hp_sdc_mlc_in(hil_mlc *mlc, suseconds_t timeout) /* printk(KERN_DEBUG PREFIX ">[%x]\n", mlc->ipacket[0]); */ goto wasup; }
do_gettimeofday(&tv);tv.tv_usec += USEC_PER_SEC * (tv.tv_sec - mlc->instart.tv_sec);if (tv.tv_usec - mlc->instart.tv_usec > mlc->intimeout) {
if (tmp.tv64 > mlc->intimeout * NSEC_PER_USEC) { /* printk("!%i %i", tv.tv_usec - mlc->instart.tv_usec, mlc->intimeout);
As I mentioned, better use ktime_to_ns() instead of accessing the tv64 member directly, but that is just a small style question.
Arnd