The sequencer client manager reports timestamps in units of unsigned 32-bit seconds/nanoseconds, but that does not suffer from the y2038 overflow because it stores only the delta since the 'last_update' time was recorded.

However, the use of the do_gettimeofday() function is problematic and we have to replace it to avoid the overflow on on 32-bit architectures.

This uses 'struct timespec64' to record 'last_update', and changes the code to use monotonic timestamps that do not suffer from leap seconds and settimeofday updates.

As a side-effect, the code can now use the timespec64_sub() helper and become more readable and also avoid a multiplication to convert from microseconds to nanoseconds.

Signed-off-by: Arnd Bergmann arnd@arndb.de --- sound/core/seq/seq_timer.c | 23 +++++++++-------------- sound/core/seq/seq_timer.h | 2 +- 2 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c index 293104926098..dcc102813aef 100644 --- a/sound/core/seq/seq_timer.c +++ b/sound/core/seq/seq_timer.c @@ -165,7 +165,7 @@ static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri, snd_seq_timer_update_tick(&tmr->tick, resolution);

/* register actual time of this timer update */ - do_gettimeofday(&tmr->last_update); + ktime_get_ts64(&tmr->last_update);

spin_unlock_irqrestore(&tmr->lock, flags);

@@ -392,7 +392,7 @@ static int seq_timer_start(struct snd_seq_timer *tmr) return -EINVAL; snd_timer_start(tmr->timeri, tmr->ticks); tmr->running = 1; - do_gettimeofday(&tmr->last_update); + ktime_get_ts64(&tmr->last_update); return 0; }

@@ -420,7 +420,7 @@ static int seq_timer_continue(struct snd_seq_timer *tmr) } snd_timer_start(tmr->timeri, tmr->ticks); tmr->running = 1; - do_gettimeofday(&tmr->last_update); + ktime_get_ts64(&tmr->last_update); return 0; }

@@ -444,17 +444,12 @@ snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr) spin_lock_irqsave(&tmr->lock, flags); cur_time = tmr->cur_time; if (tmr->running) { - struct timeval tm; - int usec; - do_gettimeofday(&tm); - usec = (int)(tm.tv_usec - tmr->last_update.tv_usec); - if (usec < 0) { - cur_time.tv_nsec += (1000000 + usec) * 1000; - cur_time.tv_sec += tm.tv_sec - tmr->last_update.tv_sec - 1; - } else { - cur_time.tv_nsec += usec * 1000; - cur_time.tv_sec += tm.tv_sec - tmr->last_update.tv_sec; - } + struct timespec64 tm; + + ktime_get_ts64(&tm); + tm = timespec64_sub(tm, tmr->last_update); + cur_time.tv_nsec = tm.tv_nsec; + cur_time.tv_sec = tm.tv_sec; snd_seq_sanity_real_time(&cur_time); } spin_unlock_irqrestore(&tmr->lock, flags); diff --git a/sound/core/seq/seq_timer.h b/sound/core/seq/seq_timer.h index 88dfb71805ae..9506b661fe5b 100644 --- a/sound/core/seq/seq_timer.h +++ b/sound/core/seq/seq_timer.h @@ -52,7 +52,7 @@ struct snd_seq_timer { unsigned int skew; unsigned int skew_base;

- struct timeval last_update; /* time of last clock update, used for interpolation */ + struct timespec64 last_update; /* time of last clock update, used for interpolation */

spinlock_t lock; };