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 recreate it on restore stage.
Thus implement show_fdinfo method which provides enough information
for that.
One of significant changes I think is the addition of @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 too.
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
v4 (by akpm@):
-Use define timerfd_show NULL for non c/r config
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Link: http://lkml.kernel.org/r/20140715215703.114365649@openvz.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/fs/timerfd.c b/fs/timerfd.c
index 0013142..77183f0 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -35,8 +35,9 @@
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 @@
if (timerfd_canceled(ctx))
return -ECANCELED;
}
+
+ ctx->settime_flags = flags & TFD_SETTIME_FLAGS;
return 0;
}
@@ -284,11 +287,40 @@
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);
+}
+#else
+#define timerfd_show NULL
+#endif
+
static const struct file_operations timerfd_fops = {
.release = timerfd_release,
.poll = timerfd_poll,
.read = timerfd_read,
.llseek = noop_llseek,
+ .show_fdinfo = timerfd_show,
};
static int timerfd_fget(int fd, struct fd *p)