sched/wait, fs/nfs: Convert wait_on_atomic_t() usage to the new wait_var_event() API

The old wait_on_atomic_t() is going to get removed, use the more
flexible wait_var_event() API instead.

No change in functionality.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 18a7626..67d19cd 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -98,8 +98,8 @@ nfs_page_free(struct nfs_page *p)
 int
 nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
 {
-	return wait_on_atomic_t(&l_ctx->io_count, nfs_wait_atomic_killable,
-			TASK_KILLABLE);
+	return wait_var_event_killable(&l_ctx->io_count,
+				       !atomic_read(&l_ctx->io_count));
 }
 
 /**
@@ -395,7 +395,7 @@ static void nfs_clear_request(struct nfs_page *req)
 	}
 	if (l_ctx != NULL) {
 		if (atomic_dec_and_test(&l_ctx->io_count)) {
-			wake_up_atomic_t(&l_ctx->io_count);
+			wake_up_var(&l_ctx->io_count);
 			if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
 				rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
 		}