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, 3 insertions, 3 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 60c737e423a1..cc5d87cfa7c0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3922,11 +3922,11 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
 		return -EINVAL;
 
 	f = fdget(pidfd);
-	if (!f.file)
+	if (!fd_file(f))
 		return -EBADF;
 
 	/* Is this a pidfd? */
-	pid = pidfd_to_pid(f.file);
+	pid = pidfd_to_pid(fd_file(f));
 	if (IS_ERR(pid)) {
 		ret = PTR_ERR(pid);
 		goto err;
@@ -3939,7 +3939,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
 	switch (flags) {
 	case 0:
 		/* Infer scope from the type of pidfd. */
-		if (f.file->f_flags & PIDFD_THREAD)
+		if (fd_file(f)->f_flags & PIDFD_THREAD)
 			type = PIDTYPE_PID;
 		else
 			type = PIDTYPE_TGID;