2.6.25-rc7

 fs

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 61983f3..10c80b5 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -25,13 +25,15 @@ struct timerfd_ctx {
    struct hrtimer tmr;
    ktime_t tintv;
    wait_queue_head_t wqh;
+   u64 ticks;
    int expired;
+   int clockid;
 };
 
 /*
  * This gets called when the timer event triggers. We set the "expired"
  * flag, but we do not re-arm the timer (in case it's necessary,
- * tintv.tv64 != 0) until the timer is read.
+ * tintv.tv64 != 0) until the timer is accessed.
  */
 static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
 {
@@ -40,13 +42,24 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
 
    spin_lock_irqsave(&ctx->wqh.lock, flags);
    ctx->expired = 1;
+   ctx->ticks++;
    wake_up_locked(&ctx->wqh);
    spin_unlock_irqrestore(&ctx->wqh.lock, flags);
 
    return HRTIMER_NORESTART;
 }
 
-static void timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
+{
+   ktime_t now, remaining;
+
+   now = ctx->tmr.base->get_time();
+   remaining = ktime_sub(ctx->tmr.expires, now);
+
+   return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;
+}
+
+static void timerfd_setup(struct timerfd_ctx *ctx, int flags,
            const struct itimerspec *ktmr)
 {
    enum hrtimer_mode htmode;
@@ -57,8 +70,9 @@ static void timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
 
    texp = timespec_to_ktime(ktmr->it_value);
    ctx->expired = 0;
+   ctx->ticks = 0;
    ctx->tintv = timespec_to_ktime(ktmr->it_interval);
-   hrtimer_init(&ctx->tmr, clockid, htmode);
+   hrtimer_init(&ctx->tmr, ctx->clockid, htmode);
    ctx->tmr.expires = texp;
    ctx->tmr.function = timerfd_tmrproc;
    if (texp.tv64 != 0)
@@ -83,7 +97,7 @@ static unsigned int timerfd_poll(struct file *file, poll_table *wait)
    poll_wait(file, &ctx->wqh, wait);
 
    spin_lock_irqsave(&ctx->wqh.lock, flags);
-   if (ctx->expired)
+   if (ctx->ticks)
       events |= POLLIN;
    spin_unlock_irqrestore(&ctx->wqh.lock, flags);
 
@@ -102,11 +116,11 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
       return -EINVAL;
    spin_lock_irq(&ctx->wqh.lock);
    res = -EAGAIN;
-   if (!ctx->expired && !(file->f_flags & O_NONBLOCK)) {
+   if (!ctx->ticks && !(file->f_flags & O_NONBLOCK)) {
       __add_wait_queue(&ctx->wqh, &wait);
       for (res = 0;;) {
          set_current_state(TASK_INTERRUPTIBLE);
-         if (ctx->expired) {
+         if (ctx->ticks) {
             res = 0;
             break;
          }
@@ -121,22 +135,21 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
       __remove_wait_queue(&ctx->wqh, &wait);
       __set_current_state(TASK_RUNNING);
    }
-   if (ctx->expired) {
-      ctx->expired = 0;
-      if (ctx->tintv.tv64 != 0) {
+   if (ctx->ticks) {
+      ticks = ctx->ticks;
+      if (ctx->expired && ctx->tintv.tv64) {
          /*
           * If tintv.tv64 != 0, this is a periodic timer that
           * needs to be re-armed. We avoid doing it in the timer
           * callback to avoid DoS attacks specifying a very
           * short timer period.
           */
-         ticks = (u64)
-            hrtimer_forward(&ctx->tmr,
-                  hrtimer_cb_get_time(&ctx->tmr),
-                  ctx->tintv);
+         ticks += hrtimer_forward_now(&ctx->tmr,
+                       ctx->tintv) - 1;
          hrtimer_restart(&ctx->tmr);
-      } else
-         ticks = 1;
+      }
+      ctx->expired = 0;
+      ctx->ticks = 0;
    }
    spin_unlock_irq(&ctx->wqh.lock);
    if (ticks)
@@ -150,76 +163,132 @@ static const struct file_operations timerfd_fops = {
    .read      = timerfd_read,
 };
 
-asmlinkage long sys_timerfd(int ufd, int clockid, int flags,
-             const struct itimerspec __user *utmr)
+static struct file *timerfd_fget(int fd)
+{
+   struct file *file;
+
+   file = fget(fd);
+   if (!file)
+      return ERR_PTR(-EBADF);
+   if (file->f_op != &timerfd_fops) {
+      fput(file);
+      return ERR_PTR(-EINVAL);
+   }
+
+   return file;
+}
+
+asmlinkage long sys_timerfd_create(int clockid, int flags)
 {
-   int error;
+   int error, ufd;
    struct timerfd_ctx *ctx;
    struct file *file;
    struct inode *inode;
-   struct itimerspec ktmr;
-
-   if (copy_from_user(&ktmr, utmr, sizeof(ktmr)))
-      return -EFAULT;
 
+   if (flags)
+      return -EINVAL;
    if (clockid != CLOCK_MONOTONIC &&
        clockid != CLOCK_REALTIME)
       return -EINVAL;
+
+   ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+   if (!ctx)
+      return -ENOMEM;
+
+   init_waitqueue_head(&ctx->wqh);
+   ctx->clockid = clockid;
+   hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS);
+
+   error = anon_inode_getfd(&ufd, &inode, &file, "[timerfd]",
+             &timerfd_fops, ctx);
+   if (error) {
+      kfree(ctx);
+      return error;
+   }
+
+   return ufd;
+}
+
+asmlinkage long sys_timerfd_settime(int ufd, int flags,
+                const struct itimerspec __user *utmr,
+                struct itimerspec __user *otmr)
+{
+   struct file *file;
+   struct timerfd_ctx *ctx;
+   struct itimerspec ktmr, kotmr;
+
+   if (copy_from_user(&ktmr, utmr, sizeof(ktmr)))
+      return -EFAULT;
+
    if (!timespec_valid(&ktmr.it_value) ||
        !timespec_valid(&ktmr.it_interval))
       return -EINVAL;
 
-   if (ufd == -1) {
-      ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
-      if (!ctx)
-         return -ENOMEM;
-
-      init_waitqueue_head(&ctx->wqh);
-
-      timerfd_setup(ctx, clockid, flags, &ktmr);
-
-      /*
-       * When we call this, the initialization must be complete, since
-       * anon_inode_getfd() will install the fd.
-       */
-      error = anon_inode_getfd(&ufd, &inode, &file, "[timerfd]",
-                &timerfd_fops, ctx);
-      if (error)
-         goto err_tmrcancel;
-   } else {
-      file = fget(ufd);
-      if (!file)
-         return -EBADF;
-      ctx = file->private_data;
-      if (file->f_op != &timerfd_fops) {
-         fput(file);
-         return -EINVAL;
-      }
-      /*
-       * We need to stop the existing timer before reprogramming
-       * it to the new values.
-       */
-      for (;;) {
-         spin_lock_irq(&ctx->wqh.lock);
-         if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
-            break;
-         spin_unlock_irq(&ctx->wqh.lock);
-         cpu_relax();
-      }
-      /*
-       * Re-program the timer to the new value ...
-       */
-      timerfd_setup(ctx, clockid, flags, &ktmr);
+   file = timerfd_fget(ufd);
+   if (IS_ERR(file))
+      return PTR_ERR(file);
+   ctx = file->private_data;
 
+   /*
+    * We need to stop the existing timer before reprogramming
+    * it to the new values.
+    */
+   for (;;) {
+      spin_lock_irq(&ctx->wqh.lock);
+      if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
+         break;
       spin_unlock_irq(&ctx->wqh.lock);
-      fput(file);
+      cpu_relax();
    }
 
-   return ufd;
+   /*
+    * If the timer is expired and it's periodic, we need to advance it
+    * because the caller may want to know the previous expiration time.
+    * We do not update "ticks" and "expired" since the timer will be
+    * re-programmed again in the following timerfd_setup() call.
+    */
+   if (ctx->expired && ctx->tintv.tv64)
+      hrtimer_forward_now(&ctx->tmr, ctx->tintv);
 
-err_tmrcancel:
-   hrtimer_cancel(&ctx->tmr);
-   kfree(ctx);
-   return error;
+   kotmr.it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
+   kotmr.it_interval = ktime_to_timespec(ctx->tintv);
+
+   /*
+    * Re-program the timer to the new value ...
+    */
+   timerfd_setup(ctx, flags, &ktmr);
+
+   spin_unlock_irq(&ctx->wqh.lock);
+   fput(file);
+   if (otmr && copy_to_user(otmr, &kotmr, sizeof(kotmr)))
+      return -EFAULT;
+
+   return 0;
+}
+
+asmlinkage long sys_timerfd_gettime(int ufd, struct itimerspec __user *otmr)
+{
+   struct file *file;
+   struct timerfd_ctx *ctx;
+   struct itimerspec kotmr;
+
+   file = timerfd_fget(ufd);
+   if (IS_ERR(file))
+      return PTR_ERR(file);
+   ctx = file->private_data;
+
+   spin_lock_irq(&ctx->wqh.lock);
+   if (ctx->expired && ctx->tintv.tv64) {
+      ctx->expired = 0;
+      ctx->ticks +=
+         hrtimer_forward_now(&ctx->tmr, ctx->tintv) - 1;
+      hrtimer_restart(&ctx->tmr);
+   }
+   kotmr.it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
+   kotmr.it_interval = ktime_to_timespec(ctx->tintv);
+   spin_unlock_irq(&ctx->wqh.lock);
+   fput(file);
+
+   return copy_to_user(otmr, &kotmr, sizeof(kotmr)) ? -EFAULT: 0;
 }