timerfd: Implement show_fdinfo method (af9c4957) · Commits · 戴 / test

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>

fs/timerfd.c

+33 −1

Original line number	Diff line number	Diff line
		@@ -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_ctx *ctx, int flags,
		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 file, char __user buf, size_t count,
		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)

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