introduce fd_file(), convert all accessors to it.

	For any changes of struct fd representation we need to
turn existing accesses to fields into calls of wrappers.
Accesses to struct fd::flags are very few (3 in linux/file.h,
1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in
explicit initializers).
	Those can be dealt with in the commit converting to
new layout; accesses to struct fd::file are too many for that.
	This commit converts (almost) all of f.file to
fd_file(f).  It's not entirely mechanical ('file' is used as
a member name more than just in struct fd) and it does not
even attempt to distinguish the uses in pointer context from
those in boolean context; the latter will be eventually turned
into a separate helper (fd_empty()).

	NOTE: mass conversion to fd_empty(), tempting as it
might be, is a bad idea; better do that piecewise in commit
that convert from fdget...() to CLASS(...).

[conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c
caught by git; fs/stat.c one got caught by git grep]
[fs/xattr.c conflict]

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 6 insertions, 6 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 328087a4df8a..c46d48bb38cd 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4099,14 +4099,14 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 	}
 
 	f = fdget(fs_fd);
-	if (!f.file)
+	if (!fd_file(f))
 		return -EBADF;
 
 	ret = -EINVAL;
-	if (f.file->f_op != &fscontext_fops)
+	if (fd_file(f)->f_op != &fscontext_fops)
 		goto err_fsfd;
 
-	fc = f.file->private_data;
+	fc = fd_file(f)->private_data;
 
 	ret = mutex_lock_interruptible(&fc->uapi_mutex);
 	if (ret < 0)
@@ -4649,15 +4649,15 @@ static int build_mount_idmapped(const struct mount_attr *attr, size_t usize,
 		return -EINVAL;
 
 	f = fdget(attr->userns_fd);
-	if (!f.file)
+	if (!fd_file(f))
 		return -EBADF;
 
-	if (!proc_ns_file(f.file)) {
+	if (!proc_ns_file(fd_file(f))) {
 		err = -EINVAL;
 		goto out_fput;
 	}
 
-	ns = get_proc_ns(file_inode(f.file));
+	ns = get_proc_ns(file_inode(fd_file(f)));
 	if (ns->ops->type != CLONE_NEWUSER) {
 		err = -EINVAL;
 		goto out_fput;