From ebf918cf9922748b9d4d9bf6a2620530cdc5a1d0 Mon Sep 17 00:00:00 2001 From: Tina Ruchandani Date: Sat, 19 Mar 2016 11:21:14 -0700 Subject: isdn: Use ktime_t instead of 'struct timeval' 'struct timeval' uses 32-bit representation for seconds which will overflow in year 2038 and beyond. mISDN/clock.c needs to compute and store elapsed time in intervals of 125 microseconds. This patch replaces the usage of 'struct timeval' with 64-bit ktime_t which is y2038 safe. The patch also replaces do_gettimeofday() (wall-clock time) with ktime_get() (monotonic time) since we only care about elapsed time here. Signed-off-by: Tina Ruchandani Suggested-by: Arnd Bergmnann Suggested-by: David Miller Signed-off-by: David S. Miller --- drivers/isdn/mISDN/clock.c | 69 +++++++++++++++++++--------------------------- include/linux/mISDNif.h | 2 +- 2 files changed, 30 insertions(+), 41 deletions(-) diff --git a/drivers/isdn/mISDN/clock.c b/drivers/isdn/mISDN/clock.c index 693fb7c9b59a..f8f659f1ce1b 100644 --- a/drivers/isdn/mISDN/clock.c +++ b/drivers/isdn/mISDN/clock.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include "core.h" @@ -45,15 +46,15 @@ static u_int *debug; static LIST_HEAD(iclock_list); static DEFINE_RWLOCK(iclock_lock); static u16 iclock_count; /* counter of last clock */ -static struct timeval iclock_tv; /* time stamp of last clock */ -static int iclock_tv_valid; /* already received one timestamp */ +static ktime_t iclock_timestamp; /* time stamp of last clock */ +static int iclock_timestamp_valid; /* already received one timestamp */ static struct mISDNclock *iclock_current; void mISDN_init_clock(u_int *dp) { debug = dp; - do_gettimeofday(&iclock_tv); + iclock_timestamp = ktime_get(); } static void @@ -86,7 +87,7 @@ select_iclock(void) } if (bestclock != iclock_current) { /* no clock received yet */ - iclock_tv_valid = 0; + iclock_timestamp_valid = 0; } iclock_current = bestclock; } @@ -139,12 +140,11 @@ mISDN_unregister_clock(struct mISDNclock *iclock) EXPORT_SYMBOL(mISDN_unregister_clock); void -mISDN_clock_update(struct mISDNclock *iclock, int samples, struct timeval *tv) +mISDN_clock_update(struct mISDNclock *iclock, int samples, ktime_t *timestamp) { u_long flags; - struct timeval tv_now; - time_t elapsed_sec; - int elapsed_8000th; + ktime_t timestamp_now; + u16 delta; write_lock_irqsave(&iclock_lock, flags); if (iclock_current != iclock) { @@ -156,33 +156,27 @@ mISDN_clock_update(struct mISDNclock *iclock, int samples, struct timeval *tv) write_unlock_irqrestore(&iclock_lock, flags); return; } - if (iclock_tv_valid) { + if (iclock_timestamp_valid) { /* increment sample counter by given samples */ iclock_count += samples; - if (tv) { /* tv must be set, if function call is delayed */ - iclock_tv.tv_sec = tv->tv_sec; - iclock_tv.tv_usec = tv->tv_usec; - } else - do_gettimeofday(&iclock_tv); + if (timestamp) { /* timestamp must be set, if function call is delayed */ + iclock_timestamp = *timestamp; + } else { + iclock_timestamp = ktime_get(); + } } else { /* calc elapsed time by system clock */ - if (tv) { /* tv must be set, if function call is delayed */ - tv_now.tv_sec = tv->tv_sec; - tv_now.tv_usec = tv->tv_usec; - } else - do_gettimeofday(&tv_now); - elapsed_sec = tv_now.tv_sec - iclock_tv.tv_sec; - elapsed_8000th = (tv_now.tv_usec / 125) - - (iclock_tv.tv_usec / 125); - if (elapsed_8000th < 0) { - elapsed_sec -= 1; - elapsed_8000th += 8000; + if (timestamp) { /* timestamp must be set, if function call is delayed */ + timestamp_now = *timestamp; + } else { + timestamp_now = ktime_get(); } + delta = ktime_divns(ktime_sub(timestamp_now, iclock_timestamp), + (NSEC_PER_SEC / 8000)); /* add elapsed time to counter and set new timestamp */ - iclock_count += elapsed_sec * 8000 + elapsed_8000th; - iclock_tv.tv_sec = tv_now.tv_sec; - iclock_tv.tv_usec = tv_now.tv_usec; - iclock_tv_valid = 1; + iclock_count += delta; + iclock_timestamp = timestamp_now; + iclock_timestamp_valid = 1; if (*debug & DEBUG_CLOCK) printk("Received first clock from source '%s'.\n", iclock_current ? iclock_current->name : "nothing"); @@ -195,22 +189,17 @@ unsigned short mISDN_clock_get(void) { u_long flags; - struct timeval tv_now; - time_t elapsed_sec; - int elapsed_8000th; + ktime_t timestamp_now; + u16 delta; u16 count; read_lock_irqsave(&iclock_lock, flags); /* calc elapsed time by system clock */ - do_gettimeofday(&tv_now); - elapsed_sec = tv_now.tv_sec - iclock_tv.tv_sec; - elapsed_8000th = (tv_now.tv_usec / 125) - (iclock_tv.tv_usec / 125); - if (elapsed_8000th < 0) { - elapsed_sec -= 1; - elapsed_8000th += 8000; - } + timestamp_now = ktime_get(); + delta = ktime_divns(ktime_sub(timestamp_now, iclock_timestamp), + (NSEC_PER_SEC / 8000)); /* add elapsed time to counter */ - count = iclock_count + elapsed_sec * 8000 + elapsed_8000th; + count = iclock_count + delta; read_unlock_irqrestore(&iclock_lock, flags); return count; } diff --git a/include/linux/mISDNif.h b/include/linux/mISDNif.h index 246a3529ecf6..ac02c54520e9 100644 --- a/include/linux/mISDNif.h +++ b/include/linux/mISDNif.h @@ -596,7 +596,7 @@ static inline struct mISDNdevice *dev_to_mISDN(struct device *dev) } extern void set_channel_address(struct mISDNchannel *, u_int, u_int); -extern void mISDN_clock_update(struct mISDNclock *, int, struct timeval *); +extern void mISDN_clock_update(struct mISDNclock *, int, ktime_t *); extern unsigned short mISDN_clock_get(void); extern const char *mISDNDevName4ch(struct mISDNchannel *); -- cgit v1.2.3