debugfs: Remove redundant access mode checks

debugfs_get_tree() can only be called if debugfs itself calls
simple_pin_fs() or register_filesystem(), and those call paths also
check the access mode.

debugfs_start_creating() checks the access mode so the checks in the
debugfs_create_* functions are unnecessary.

An upcoming change will affect debugfs_allow, so doing this cleanup
first will make that change simpler.

Signed-off-by: Aaron Thompson <dev@aaront.org>
Link: https://patch.msgid.link/20251120102222.18371-2-dev@null.aaront.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: dev-aaront-org

fs/debugfs/inode.c

@@ -287,9 +287,6 @@ static int debugfs_get_tree(struct fs_context *fc)
 {
 	int err;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API))
-		return -EPERM;
-
 	err = get_tree_single(fc, debugfs_fill_super);
 	if (err)
 		return err;
@@ -434,11 +431,6 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
 	if (IS_ERR(dentry))
 		return dentry;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
-		failed_creating(dentry);
-		return ERR_PTR(-EPERM);
-	}
-
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create file '%s'\n",
@@ -584,11 +576,6 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 	if (IS_ERR(dentry))
 		return dentry;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
-		failed_creating(dentry);
-		return ERR_PTR(-EPERM);
-	}
-
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create directory '%s'\n",
@@ -631,11 +618,6 @@ struct dentry *debugfs_create_automount(const char *name,
 	if (IS_ERR(dentry))
 		return dentry;
 
-	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
-		failed_creating(dentry);
-		return ERR_PTR(-EPERM);
-	}
-
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create automount '%s'\n",