2 files changed, 42 insertions, 0 deletions

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 77183f047f65..709603cac9e6 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -315,12 +315,49 @@ static int timerfd_show(struct seq_file *m, struct file *file)
 #define timerfd_show NULL
 #endif
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+        struct timerfd_ctx *ctx = file->private_data;
+        int ret = 0;
+
+        switch (cmd) {
+        case TFD_IOC_SET_TICKS: {
+                u64 ticks;
+
+                if (copy_from_user(&ticks, (u64 __user *)arg, sizeof(ticks)))
+                        return -EFAULT;
+                if (!ticks)
+                        return -EINVAL;
+
+                spin_lock_irq(&ctx->wqh.lock);
+                if (!timerfd_canceled(ctx)) {
+                        ctx->ticks = ticks;
+                        if (ticks)
+                                wake_up_locked(&ctx->wqh);
+                } else
+                        ret = -ECANCELED;
+                spin_unlock_irq(&ctx->wqh.lock);
+                break;
+        }
+        default:
+                ret = -ENOTTY;
+                break;
+        }
+
+        return ret;
+}
+#else
+#define timerfd_ioctl 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,
+        .unlocked_ioctl = timerfd_ioctl,
 };
 
 static int timerfd_fget(int fd, struct fd *p)
diff --git a/include/linux/timerfd.h b/include/linux/timerfd.h
index d3b57fa12225..bd36ce431e32 100644
--- a/include/linux/timerfd.h
+++ b/include/linux/timerfd.h
@@ -11,6 +11,9 @@
 /* For O_CLOEXEC and O_NONBLOCK */
 #include <linux/fcntl.h>
 
+/* For _IO helpers */
+#include <linux/ioctl.h>
+
 /*
  * CAREFUL: Check include/asm-generic/fcntl.h when defining
  * new flags, since they might collide with O_* ones. We want
@@ -29,4 +32,6 @@
 /* Flags for timerfd_settime.  */
 #define TFD_SETTIME_FLAGS (TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET)
 
+#define TFD_IOC_SET_TICKS       _IOW('T', 0, u64)
+
 #endif /* _LINUX_TIMERFD_H */