[RFC PATCH v1 03/13] file: expose helpers for in-kernel fd actions

[Li Chen]

Split do_close_range() from the close_range syscall wrapper and make
ksys_dup3() available to in-kernel callers. Later spawn-template fd
actions use these helpers instead of duplicating close and dup logic.

Signed-off-by: Li Chen <me@linux.beauty>
---
 fs/file.c               | 11 ++++++++---
 include/linux/fdtable.h |  2 ++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index e5c75b22e0c7c..a9f4b4e2dcd45 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -815,8 +815,7 @@ static inline void __range_close(struct files_struct *files, unsigned int fd,
  * from @fd up to and including @max_fd are closed.
  * Currently, errors to close a given file descriptor are ignored.
  */
-SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
-		unsigned int, flags)
+int do_close_range(unsigned int fd, unsigned int max_fd, unsigned int flags)
 {
 	struct task_struct *me = current;
 	struct files_struct *cur_fds = me->files, *fds = NULL;
@@ -867,6 +866,12 @@ SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
 	return 0;
 }
 
+SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
+		unsigned int, flags)
+{
+	return do_close_range(fd, max_fd, flags);
+}
+
 /**
  * file_close_fd - return file associated with fd
  * @fd: file descriptor to retrieve file for
@@ -1421,7 +1426,7 @@ int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)
 	return new_fd;
 }
 
-static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
+int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
 {
 	int err = -EBADF;
 	struct file *file;
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index c45306a9f0072..7f852fcc082a4 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -112,6 +112,8 @@ int iterate_fd(struct files_struct *, unsigned,
 
 extern int close_fd(unsigned int fd);
 extern struct file *file_close_fd(unsigned int fd);
+int do_close_range(unsigned int fd, unsigned int max_fd, unsigned int flags);
+int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags);
 
 extern struct kmem_cache *files_cachep;
 
-- 
2.52.0