From: Cyrill Gorcunov Subject: timerfd: Implement show_fdinfo method For checkpoint/restore of timerfd files we need to know how exactly the timer were armed to be able to handle it. Thus implement show_fdinfo method which provides enough information for timer re-creation. One of significant changes I think is addition of timerfd_ctx::settime_flags member. Currently there are two flags TFD_TIMER_ABSTIME and TFD_TIMER_CANCEL_ON_SET, and the second can be found from @might_cancel variable but in case if the flags will be extended in future we most probably will have to somehow remember them explicitly anyway so I guss doing that right now won't hurt. To not bloat the timerfd_ctx structure I've converted @expired to short integer and defined @settime_flags as short as well. v2 (by avagin@, vdavydov@ and tglx@): - Add it_value/it_interval fields - Save flags being used in timerfd_setup in context v3 (by tglx@): - don't forget to use CONFIG_PROC_FS CC: Shawn Landden CC: Thomas Gleixner CC: Andrew Morton CC: Andrey Vagin CC: Pavel Emelyanov CC: Vladimir Davydov Signed-off-by: Cyrill Gorcunov --- fs/timerfd.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) Index: linux-2.6.git/fs/timerfd.c =================================================================== --- linux-2.6.git.orig/fs/timerfd.c +++ linux-2.6.git/fs/timerfd.c @@ -35,8 +35,9 @@ struct timerfd_ctx { ktime_t moffs; wait_queue_head_t wqh; u64 ticks; - int expired; int clockid; + short unsigned expired; + short unsigned settime_flags; /* to show in fdinfo */ struct rcu_head rcu; struct list_head clist; bool might_cancel; @@ -196,6 +197,8 @@ static int timerfd_setup(struct timerfd_ if (timerfd_canceled(ctx)) return -ECANCELED; } + + ctx->settime_flags = flags & TFD_SETTIME_FLAGS; return 0; } @@ -284,11 +287,40 @@ static ssize_t timerfd_read(struct file return res; } +#ifdef CONFIG_PROC_FS +static int timerfd_show(struct seq_file *m, struct file *file) +{ + struct timerfd_ctx *ctx = file->private_data; + struct itimerspec t; + + spin_lock_irq(&ctx->wqh.lock); + t.it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); + t.it_interval = ktime_to_timespec(ctx->tintv); + spin_unlock_irq(&ctx->wqh.lock); + + return seq_printf(m, + "clockid: %d\n" + "ticks: %llu\n" + "settime flags: 0%o\n" + "it_value: (%llu, %llu)\n" + "it_interval: (%llu, %llu)\n", + ctx->clockid, (unsigned long long)ctx->ticks, + ctx->settime_flags, + (unsigned long long)t.it_value.tv_sec, + (unsigned long long)t.it_value.tv_nsec, + (unsigned long long)t.it_interval.tv_sec, + (unsigned long long)t.it_interval.tv_nsec); +} +#endif + static const struct file_operations timerfd_fops = { .release = timerfd_release, .poll = timerfd_poll, .read = timerfd_read, .llseek = noop_llseek, +#ifdef CONFIG_PROC_FS + .show_fdinfo = timerfd_show, +#endif }; static int timerfd_fget(int fd, struct fd *p)