Merge branch 'linus' into locking-for-linus

Conflicts:
	lib/Kconfig.debug

1 files changed, 30 insertions, 12 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 8fa77e23394..76da1253795 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -443,7 +443,7 @@ static struct kiocb *__aio_get_req(struct kioctx *ctx)
 	req->private = NULL;
 	req->ki_iovec = NULL;
 	INIT_LIST_HEAD(&req->ki_run_list);
-	req->ki_eventfd = ERR_PTR(-EINVAL);
+	req->ki_eventfd = NULL;
 
 	/* Check if the completion queue has enough free space to
 	 * accept an event from this io.
@@ -485,8 +485,6 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
 {
 	assert_spin_locked(&ctx->ctx_lock);
 
-	if (!IS_ERR(req->ki_eventfd))
-		fput(req->ki_eventfd);
 	if (req->ki_dtor)
 		req->ki_dtor(req);
 	if (req->ki_iovec != &req->ki_inline_vec)
@@ -508,8 +506,11 @@ static void aio_fput_routine(struct work_struct *data)
 		list_del(&req->ki_list);
 		spin_unlock_irq(&fput_lock);
 
-		/* Complete the fput */
-		__fput(req->ki_filp);
+		/* Complete the fput(s) */
+		if (req->ki_filp != NULL)
+			__fput(req->ki_filp);
+		if (req->ki_eventfd != NULL)
+			__fput(req->ki_eventfd);
 
 		/* Link the iocb into the context's free list */
 		spin_lock_irq(&ctx->ctx_lock);
@@ -527,12 +528,14 @@ static void aio_fput_routine(struct work_struct *data)
  */
 static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
 {
+	int schedule_putreq = 0;
+
 	dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
 		req, atomic_long_read(&req->ki_filp->f_count));
 
 	assert_spin_locked(&ctx->ctx_lock);
 
-	req->ki_users --;
+	req->ki_users--;
 	BUG_ON(req->ki_users < 0);
 	if (likely(req->ki_users))
 		return 0;
@@ -540,10 +543,23 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
 	req->ki_cancel = NULL;
 	req->ki_retry = NULL;
 
-	/* Must be done under the lock to serialise against cancellation.
-	 * Call this aio_fput as it duplicates fput via the fput_work.
+	/*
+	 * Try to optimize the aio and eventfd file* puts, by avoiding to
+	 * schedule work in case it is not __fput() time. In normal cases,
+	 * we would not be holding the last reference to the file*, so
+	 * this function will be executed w/out any aio kthread wakeup.
 	 */
-	if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count))) {
+	if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count)))
+		schedule_putreq++;
+	else
+		req->ki_filp = NULL;
+	if (req->ki_eventfd != NULL) {
+		if (unlikely(atomic_long_dec_and_test(&req->ki_eventfd->f_count)))
+			schedule_putreq++;
+		else
+			req->ki_eventfd = NULL;
+	}
+	if (unlikely(schedule_putreq)) {
 		get_ioctx(ctx);
 		spin_lock(&fput_lock);
 		list_add(&req->ki_list, &fput_head);
@@ -571,7 +587,7 @@ int aio_put_req(struct kiocb *req)
 static struct kioctx *lookup_ioctx(unsigned long ctx_id)
 {
 	struct mm_struct *mm = current->mm;
-	struct kioctx *ctx = NULL;
+	struct kioctx *ctx, *ret = NULL;
 	struct hlist_node *n;
 
 	rcu_read_lock();
@@ -579,12 +595,13 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
 	hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
 		if (ctx->user_id == ctx_id && !ctx->dead) {
 			get_ioctx(ctx);
+			ret = ctx;
 			break;
 		}
 	}
 
 	rcu_read_unlock();
-	return ctx;
+	return ret;
 }
 
 /*
@@ -1009,7 +1026,7 @@ int aio_complete(struct kiocb *iocb, long res, long res2)
 	 * eventfd. The eventfd_signal() function is safe to be called
 	 * from IRQ context.
 	 */
-	if (!IS_ERR(iocb->ki_eventfd))
+	if (iocb->ki_eventfd != NULL)
 		eventfd_signal(iocb->ki_eventfd, 1);
 
 put_rq:
@@ -1608,6 +1625,7 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
 		req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd);
 		if (IS_ERR(req->ki_eventfd)) {
 			ret = PTR_ERR(req->ki_eventfd);
+			req->ki_eventfd = NULL;
 			goto out_put_req;
 		}
 	}