UBIFS: slightly optimize write-buffer timer usage

This patch adds the following minor optimization:

1. If write-buffer does not use the timer, indicate it with the
   wbuf->no_timer variable, instead of using the wbuf->softlimit
   variable. This is better because wbuf->softlimit is of ktime_t
   type, and the ktime_to_ns function contains 64-bit multiplication.

2. Do not call the 'hrtimer_cancel()' function for write-buffers
   which do not use timers.

3. Do not cancel the timer in 'ubifs_put_super()' because the
   synchronization function does this.

This patch also removes a confusing comment.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 1bf01d820066..97bc9d09d54b 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -654,7 +654,8 @@ typedef int (*ubifs_lpt_scan_callback)(struct ubifs_info *c,
  * @delta: hard and soft timeouts delta (the timer expire inteval is @softlimit
  *         and @softlimit + @delta)
  * @timer: write-buffer timer
- * @need_sync: it is set if its timer expired and needs sync
+ * @no_timer: non-zero if this write-buffer does not timer
+ * @need_sync: non-zero if its timer expired and needs sync
  * @next_ino: points to the next position of the following inode number
  * @inodes: stores the inode numbers of the nodes which are in wbuf
  *
@@ -683,7 +684,8 @@ struct ubifs_wbuf {
         ktime_t softlimit;
         unsigned long long delta;
         struct hrtimer timer;
-        int need_sync;
+        unsigned int no_timer:1;
+        unsigned int need_sync:1;
         int next_ino;
         ino_t *inodes;
 };