Subject: [PATCH 38/39] css_set_fork(): switch to CLASS(fd_raw, ...)

From: [email-masked]
Date: Tue, 30 Jul 2024 01:16:24 -0400

From: Al Viro <[email-masked]>

reference acquired there by fget_raw() is not stashed anywhere -
we could as well borrow instead.

Signed-off-by: Al Viro <[email-masked]>
---
 kernel/cgroup/cgroup.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 1244a8c8878e..0838301e4f65 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6409,7 +6409,6 @@ static int cgroup_css_set_fork(struct kernel_clone_args *kargs)
 	struct cgroup *dst_cgrp = NULL;
 	struct css_set *cset;
 	struct super_block *sb;
-	struct file *f;
 
 	if (kargs->flags & CLONE_INTO_CGROUP)
 		cgroup_lock();
@@ -6426,14 +6425,14 @@ static int cgroup_css_set_fork(struct kernel_clone_args *kargs)
 		return 0;
 	}
 
-	f = fget_raw(kargs->cgroup);
-	if (!f) {
+	CLASS(fd_raw, f)(kargs->cgroup);
+	if (fd_empty(f)) {
 		ret = -EBADF;
 		goto err;
 	}
-	sb = f->f_path.dentry->d_sb;
+	sb = fd_file(f)->f_path.dentry->d_sb;
 
-	dst_cgrp = cgroup_get_from_file(f);
+	dst_cgrp = cgroup_get_from_file(fd_file(f));
 	if (IS_ERR(dst_cgrp)) {
 		ret = PTR_ERR(dst_cgrp);
 		dst_cgrp = NULL;
@@ -6481,15 +6480,12 @@ static int cgroup_css_set_fork(struct kernel_clone_args *kargs)
 	}
 
 	put_css_set(cset);
-	fput(f);
 	kargs->cgrp = dst_cgrp;
 	return ret;
 
 err:
 	cgroup_threadgroup_change_end(current);
 	cgroup_unlock();
-	if (f)
-		fput(f);
 	if (dst_cgrp)
 		cgroup_put(dst_cgrp);
 	put_css_set(cset);
-- 
2.39.2