Commit 273ef9509b79 ("drivers/char/hpet.c: fix periodic-emulation for
delayed interrupt") removed the reference to local variable 'm', but
forgot to remove the definition and assignment of it. Due to
read_counter() indirectly calls "read barrier", the performance is
slightly degraded.
Since the following comments give some description based on 'm', so move
the assignment of 'm' into it.
Fixes: 273ef9509b79 ("drivers/char/hpet.c: fix periodic-emulation for delayed
interrupt")
Reported-by: Hulk Robot <hul...@huawei.com>
Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>
---
drivers/char/hpet.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index ed3b7dab678dbd1..46950a0cda181a1 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -156,14 +156,16 @@ static irqreturn_t hpet_interrupt(int irq, void *data)
* This has the effect of treating non-periodic like periodic.
*/
if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
- unsigned long m, t, mc, base, k;
+ unsigned long t, mc, base, k;
struct hpet __iomem *hpet = devp->hd_hpet;
struct hpets *hpetp = devp->hd_hpets;
t = devp->hd_ireqfreq;
- m = read_counter(&devp->hd_timer->hpet_compare);
mc = read_counter(&hpet->hpet_mc);
- /* The time for the next interrupt would logically be t + m,
+ /*
+ * m = read_counter(&devp->hd_timer->hpet_compare);
+ *
+ * The time for the next interrupt would logically be t + m,
* however, if we are very unlucky and the interrupt is delayed
* for longer than t then we will completely miss the next
* interrupt if we set t + m and an application will hang.
--
2.26.0.106.g9fadedd
