[PATCH] rtc: snvs: change timeout to use a fixed number of loop
From: Shawn Guo <hidden>
Date: 2012-08-16 03:03:13
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
Alexandre Belloni, Linus Torvalds
Andrew Morton [off-list ref] 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 <redacted> --- drivers/rtc/rtc-snvs.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index 912f116..3c0da33 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; }
--
1.7.5.4