From 33bf2f9b842bded48bc66a2e0d2a4c6473aa5d98 Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Wed, 26 Sep 2012 11:34:34 +1000 Subject: [PATCH] rtc: snvs: change timeout to use a fixed number of loop Andrew Morton wrote: > The timeout code here is fragile. If acquiring the spinlock takes more > than a millisecond or if this thread gets interrupted or preempted then > we could easily execute that loop just a single time, and fail. > > It would be better to retry a fixed number of times, say 1000? That > would take around 1 millisecond, but might be overkill. Take Andrew's suggestion to change the timeout code to retry 1000 times. Signed-off-by: Shawn Guo Cc: Stephen Boyd Cc: Alessandro Zummo Cc: Kim Phillips Cc: Sascha Hauer Signed-off-by: Andrew Morton --- drivers/rtc/rtc-snvs.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c index 912f11641e45..3c0da333f465 100644 --- a/drivers/rtc/rtc-snvs.c +++ b/drivers/rtc/rtc-snvs.c @@ -83,8 +83,8 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) { - unsigned long timeout = jiffies + msecs_to_jiffies(1); unsigned long flags; + int timeout = 1000; u32 lpcr; spin_lock_irqsave(&data->lock, flags); @@ -98,7 +98,7 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) spin_unlock_irqrestore(&data->lock, flags); - while (1) { + while (--timeout) { lpcr = readl(data->ioaddr + SNVS_LPCR); if (enable) { @@ -108,11 +108,11 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) if (!(lpcr & SNVS_LPCR_SRTC_ENV)) break; } - - if (time_after(jiffies, timeout)) - return -ETIMEDOUT; } + if (!timeout) + return -ETIMEDOUT; + return 0; } -- 2.39.5