FS-Cache: Bit waiting helpers

Add helpers for use with wait_on_bit().

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index 4c6ba56..1638994 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -82,6 +82,9 @@
 extern unsigned fscache_debug;
 extern struct kobject *fscache_root;
 
+extern int fscache_wait_bit(void *);
+extern int fscache_wait_bit_interruptible(void *);
+
 /*
  * fsc-proc.c
  */
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
index 48b79d2..4de41b5 100644
--- a/fs/fscache/main.c
+++ b/fs/fscache/main.c
@@ -102,3 +102,23 @@
 }
 
 module_exit(fscache_exit);
+
+/*
+ * wait_on_bit() sleep function for uninterruptible waiting
+ */
+int fscache_wait_bit(void *flags)
+{
+	schedule();
+	return 0;
+}
+EXPORT_SYMBOL(fscache_wait_bit);
+
+/*
+ * wait_on_bit() sleep function for interruptible waiting
+ */
+int fscache_wait_bit_interruptible(void *flags)
+{
+	schedule();
+	return signal_pending(current);
+}
+EXPORT_SYMBOL(fscache_wait_bit_interruptible);