file: Rename __close_fd to close_fd and remove the files parameter

[ Upstream commit 8760c909f54a82aaa6e76da19afe798a0c77c3c3 ]

The function __close_fd was added to support binder[1].  Now that
binder has been fixed to no longer need __close_fd[2] all calls
to __close_fd pass current->files.

Therefore transform the files parameter into a local variable
initialized to current->files, and rename __close_fd to close_fd to
reflect this change, and keep it in sync with the similar changes to
__alloc_fd, and __fd_install.

This removes the need for callers to care about the extra care that
needs to be take if anything except current->files is passed, by
limiting the callers to only operation on current->files.

[1] 483ce1d4b8c3 ("take descriptor-related part of close() to file.c")
[2] 44d8047f1d87 ("binder: use standard functions to allocate fds")
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
v1: https://lkml.kernel.org/r/20200817220425.9389-17-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20201120231441.29911-21-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

4 files changed, 9 insertions, 12 deletions

diff --git a/fs/file.c b/fs/file.c
index 48d0306e42cc..fdb84a64724b 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -659,11 +659,9 @@ out_unlock:
 	return file;
 }
 
-/*
- * The same warnings as for __alloc_fd()/__fd_install() apply here...
- */
-int __close_fd(struct files_struct *files, unsigned fd)
+int close_fd(unsigned fd)
 {
+	struct files_struct *files = current->files;
 	struct file *file;
 
 	file = pick_file(files, fd);
@@ -672,7 +670,7 @@ int __close_fd(struct files_struct *files, unsigned fd)
 
 	return filp_close(file, files);
 }
-EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
+EXPORT_SYMBOL(close_fd); /* for ksys_close() */
 
 /**
  * __close_range() - Close all file descriptors in a given range.
@@ -1087,7 +1085,7 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags)
 	struct files_struct *files = current->files;
 
 	if (!file)
-		return __close_fd(files, fd);
+		return close_fd(fd);
 
 	if (fd >= rlimit(RLIMIT_NOFILE))
 		return -EBADF;
diff --git a/fs/open.c b/fs/open.c
index 83f62cf1432c..48933cbb7539 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1310,7 +1310,7 @@ EXPORT_SYMBOL(filp_close);
  */
 SYSCALL_DEFINE1(close, unsigned int, fd)
 {
-	int retval = __close_fd(current->files, fd);
+	int retval = close_fd(fd);
 
 	/* can't restart close syscall because file table entry was cleared */
 	if (unlikely(retval == -ERESTARTSYS ||
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index d26b884fcc5c..4ed3589f9294 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -124,8 +124,7 @@ int iterate_fd(struct files_struct *, unsigned,
 		int (*)(const void *, struct file *, unsigned),
 		const void *);
 
-extern int __close_fd(struct files_struct *files,
-		      unsigned int fd);
+extern int close_fd(unsigned int fd);
 extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags);
 extern int close_fd_get_file(unsigned int fd, struct file **res);
 extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 17a24e1180da..0bc3dd86f9e5 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1320,16 +1320,16 @@ static inline long ksys_ftruncate(unsigned int fd, loff_t length)
 	return do_sys_ftruncate(fd, length, 1);
 }
 
-extern int __close_fd(struct files_struct *files, unsigned int fd);
+extern int close_fd(unsigned int fd);
 
 /*
  * In contrast to sys_close(), this stub does not check whether the syscall
  * should or should not be restarted, but returns the raw error codes from
- * __close_fd().
+ * close_fd().
  */
 static inline int ksys_close(unsigned int fd)
 {
-	return __close_fd(current->files, fd);
+	return close_fd(fd);
 }
 
 extern long do_sys_truncate(const char __user *pathname, loff_t length);