new helper: daemonize_descriptors()

descriptor-related parts of daemonize, done right.  As the
result we simplify the locking rules for ->files - we
hold task_lock in *all* cases when we modify ->files.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/file.c b/fs/file.c
index e6e41812258..15750b80e3c 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -519,6 +519,12 @@ struct files_struct init_files = {
 	.file_lock	= __SPIN_LOCK_UNLOCKED(init_task.file_lock),
 };
 
+void daemonize_descriptors(void)
+{
+	atomic_inc(&init_files.count);
+	reset_files_struct(&init_files);
+}
+
 /*
  * allocate a file descriptor, mark it busy.
  */