Remove struct task_struct::io_wait

Hell knows what happened in commit 63b05203af57e7de4f3bb63b8b81d43bc196d32b
during 2.6.9 development.  Commit introduced io_wait field which remained
write-only than and still remains write-only.

Also garbage collect macros which "use" io_wait.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 14 deletions

diff --git a/fs/aio.c b/fs/aio.c
index d02f43b50a3d..f12db415c0f6 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -710,18 +710,9 @@ static ssize_t aio_run_iocb(struct kiocb *iocb)
 
         /*
          * Now we are all set to call the retry method in async
-         * context. By setting this thread's io_wait context
-         * to point to the wait queue entry inside the currently
-         * running iocb for the duration of the retry, we ensure
-         * that async notification wakeups are queued by the
-         * operation instead of blocking waits, and when notified,
-         * cause the iocb to be kicked for continuation (through
-         * the aio_wake_function callback).
+         * context.
          */
-        BUG_ON(current->io_wait != NULL);
-        current->io_wait = &iocb->ki_wait;
         ret = retry(iocb);
-        current->io_wait = NULL;
 
         if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
                 BUG_ON(!list_empty(&iocb->ki_wait.task_list));
@@ -1508,10 +1499,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb)
  *      Simply triggers a retry of the operation via kick_iocb.
  *
  *      This callback is specified in the wait queue entry in
- *      a kiocb (current->io_wait points to this wait queue
- *      entry when an aio operation executes; it is used
- *      instead of a synchronous wait when an i/o blocking
- *      condition is encountered during aio).
+ *      a kiocb.
  *
  * Note:
  * This routine is executed with the wait queue lock held.