[PATCH V3 2/2] hil_mlc: convert timeval to jiffies

From: WEN Pingbo
Date: Sat Oct 24 2015 - 00:01:33 EST


struct timeval is not y2038 safe, and what mlc->instart do is
scheduling a task in a fixed timeout, so jiffies is the
simplest choice here.

In hilse_donode(), the expires in mod_timer equals

jiffies + intimeout - (now - instart)

If we use jiffies in 'now', the expires equals

instart + intimeout

So, all we need to do is that making sure expires is a future
timestamp before passed it to mod_timer

Signed-off-by: WEN Pingbo <pingbo.wen@xxxxxxxxxx>
---

Version 2:
Using ktime_t to fix y2038 problem
Version 3:
Convert it to jiffies

drivers/input/serio/hil_mlc.c | 17 +++++++----------
drivers/input/serio/hp_sdc_mlc.c | 7 +++----
include/linux/hil_mlc.h | 2 +-
3 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/input/serio/hil_mlc.c b/drivers/input/serio/hil_mlc.c
index fb297aa..5428098 100644
--- a/drivers/input/serio/hil_mlc.c
+++ b/drivers/input/serio/hil_mlc.c
@@ -603,7 +603,7 @@ static inline void hilse_setup_input(hil_mlc *mlc, const struct hilse_node *node
}
mlc->istarted = 1;
mlc->intimeout = node->arg;
- do_gettimeofday(&(mlc->instart));
+ mlc->instart = jiffies;
mlc->icount = 15;
memset(mlc->ipacket, 0, 16 * sizeof(hil_packet));
BUG_ON(down_trylock(&mlc->isem));
@@ -708,7 +708,7 @@ static int hilse_donode(hil_mlc *mlc)
break;
}
mlc->ostarted = 0;
- do_gettimeofday(&(mlc->instart));
+ mlc->instart = jiffies;
write_unlock_irqrestore(&mlc->lock, flags);
nextidx = HILSEN_NEXT;
break;
@@ -729,18 +729,15 @@ static int hilse_donode(hil_mlc *mlc)
#endif

while (nextidx & HILSEN_SCHED) {
- struct timeval tv;
+ unsigned long expires = mlc->instart +
+ usecs_to_jiffies(mlc->intimeout);

if (!sched_long)
goto sched;

- 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 (time_after_eq(jiffies, expires))
+ goto sched;
+ mod_timer(&hil_mlcs_kicker, expires);
break;
sched:
tasklet_schedule(&hil_mlcs_tasklet);
diff --git a/drivers/input/serio/hp_sdc_mlc.c b/drivers/input/serio/hp_sdc_mlc.c
index d50f067..b91d5bb 100644
--- a/drivers/input/serio/hp_sdc_mlc.c
+++ b/drivers/input/serio/hp_sdc_mlc.c
@@ -149,7 +149,6 @@ 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;
if (priv->emtestmode) {
mlc->ipacket[0] =
HIL_ERR_INT | (mlc->opacket &
@@ -160,9 +159,9 @@ 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 (time_after(jiffies,
+ mlc->instart + usecs_to_jiffies(mlc->intimeout))) {
/* printk("!%i %i",
tv.tv_usec - mlc->instart.tv_usec,
mlc->intimeout);
diff --git a/include/linux/hil_mlc.h b/include/linux/hil_mlc.h
index 29bb5e3..feb167d 100644
--- a/include/linux/hil_mlc.h
+++ b/include/linux/hil_mlc.h
@@ -144,7 +144,7 @@ struct hil_mlc {
hil_packet ipacket[16];
hil_packet imatch;
int icount;
- struct timeval instart;
+ unsigned long instart; /* in jiffies */
suseconds_t intimeout;

int ddi; /* Last operational device id */
--
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/