Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 4ca0b5c..6ebae6b 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * fs/kernfs/dir.c - kernfs directory implementation
  *
  * Copyright (c) 2001-3 Patrick Mochel
  * Copyright (c) 2007 SUSE Linux Products GmbH
  * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
- *
- * This file is released under the GPLv2.
  */
 
 #include <linux/sched.h>
@@ -138,6 +137,9 @@
 	if (kn_from == kn_to)
 		return strlcpy(buf, "/", buflen);
 
+	if (!buf)
+		return -EINVAL;
+
 	common = kernfs_common_ancestor(kn_from, kn_to);
 	if (WARN_ON(!common))
 		return -EINVAL;
@@ -145,8 +147,7 @@
 	depth_to = kernfs_depth(common, kn_to);
 	depth_from = kernfs_depth(common, kn_from);
 
-	if (buf)
-		buf[0] = '\0';
+	buf[0] = '\0';
 
 	for (i = 0; i < depth_from; i++)
 		len += strlcpy(buf + len, parent_str,
@@ -431,7 +432,6 @@
  */
 void kernfs_put_active(struct kernfs_node *kn)
 {
-	struct kernfs_root *root = kernfs_root(kn);
 	int v;
 
 	if (unlikely(!kn))
@@ -443,7 +443,7 @@
 	if (likely(v != KN_DEACTIVATED_BIAS))
 		return;
 
-	wake_up_all(&root->deactivate_waitq);
+	wake_up_all(&kernfs_root(kn)->deactivate_waitq);
 }
 
 /**
@@ -532,12 +532,9 @@
 	kfree_const(kn->name);
 
 	if (kn->iattr) {
-		if (kn->iattr->ia_secdata)
-			security_release_secctx(kn->iattr->ia_secdata,
-						kn->iattr->ia_secdata_len);
 		simple_xattrs_free(&kn->iattr->xattrs);
+		kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
 	}
-	kfree(kn->iattr);
 	spin_lock(&kernfs_idr_lock);
 	idr_remove(&root->ino_idr, kn->id.ino);
 	spin_unlock(&kernfs_idr_lock);
@@ -618,6 +615,7 @@
 }
 
 static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
+					     struct kernfs_node *parent,
 					     const char *name, umode_t mode,
 					     kuid_t uid, kgid_t gid,
 					     unsigned flags)
@@ -650,11 +648,10 @@
 	kn->id.generation = gen;
 
 	/*
-	 * set ino first. This barrier is paired with atomic_inc_not_zero in
+	 * set ino first. This RELEASE is paired with atomic_inc_not_zero in
 	 * kernfs_find_and_get_node_by_ino
 	 */
-	smp_mb__before_atomic();
-	atomic_set(&kn->count, 1);
+	atomic_set_release(&kn->count, 1);
 	atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
 	RB_CLEAR_NODE(&kn->rb);
 
@@ -674,6 +671,12 @@
 			goto err_out3;
 	}
 
+	if (parent) {
+		ret = security_kernfs_init_security(parent, kn);
+		if (ret)
+			goto err_out3;
+	}
+
 	return kn;
 
  err_out3:
@@ -692,7 +695,7 @@
 {
 	struct kernfs_node *kn;
 
-	kn = __kernfs_new_node(kernfs_root(parent),
+	kn = __kernfs_new_node(kernfs_root(parent), parent,
 			       name, mode, uid, gid, flags);
 	if (kn) {
 		kernfs_get(parent);
@@ -795,9 +798,8 @@
 	/* Update timestamps on the parent */
 	ps_iattr = parent->iattr;
 	if (ps_iattr) {
-		struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
-		ktime_get_real_ts64(&ps_iattrs->ia_ctime);
-		ps_iattrs->ia_mtime = ps_iattrs->ia_ctime;
+		ktime_get_real_ts64(&ps_iattr->ia_ctime);
+		ps_iattr->ia_mtime = ps_iattr->ia_ctime;
 	}
 
 	mutex_unlock(&kernfs_mutex);
@@ -962,7 +964,7 @@
 	INIT_LIST_HEAD(&root->supers);
 	root->next_generation = 1;
 
-	kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
+	kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO,
 			       GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
 			       KERNFS_DIR);
 	if (!kn) {
@@ -1329,9 +1331,8 @@
 
 			/* update timestamps on the parent */
 			if (ps_iattr) {
-				ktime_get_real_ts64(&ps_iattr->ia_iattr.ia_ctime);
-				ps_iattr->ia_iattr.ia_mtime =
-					ps_iattr->ia_iattr.ia_ctime;
+				ktime_get_real_ts64(&ps_iattr->ia_ctime);
+				ps_iattr->ia_mtime = ps_iattr->ia_ctime;
 			}
 
 			kernfs_put(pos);