Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 2ada5e2..a70f720 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Minimal file system backend for holding eBPF maps and programs,
  * used by bpf(2) object pinning.
@@ -5,10 +6,6 @@
  * Authors:
  *
  *	Daniel Borkmann <daniel@iogearbox.net>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
  */
 
 #include <linux/init.h>
@@ -17,8 +14,9 @@
 #include <linux/mount.h>
 #include <linux/namei.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/kdev_t.h>
-#include <linux/parser.h>
 #include <linux/filter.h>
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
@@ -518,7 +516,7 @@
 static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type)
 {
 	struct bpf_prog *prog;
-	int ret = inode_permission(inode, MAY_READ | MAY_WRITE);
+	int ret = inode_permission(inode, MAY_READ);
 	if (ret)
 		return ERR_PTR(ret);
 
@@ -554,19 +552,6 @@
 }
 EXPORT_SYMBOL(bpf_prog_get_type_path);
 
-static void bpf_evict_inode(struct inode *inode)
-{
-	enum bpf_type type;
-
-	truncate_inode_pages_final(&inode->i_data);
-	clear_inode(inode);
-
-	if (S_ISLNK(inode->i_mode))
-		kfree(inode->i_link);
-	if (!bpf_inode_type(inode, &type))
-		bpf_any_put(inode->i_private, type);
-}
-
 /*
  * Display the mount options in /proc/mounts.
  */
@@ -579,67 +564,72 @@
 	return 0;
 }
 
+static void bpf_free_inode(struct inode *inode)
+{
+	enum bpf_type type;
+
+	if (S_ISLNK(inode->i_mode))
+		kfree(inode->i_link);
+	if (!bpf_inode_type(inode, &type))
+		bpf_any_put(inode->i_private, type);
+	free_inode_nonrcu(inode);
+}
+
 static const struct super_operations bpf_super_ops = {
 	.statfs		= simple_statfs,
 	.drop_inode	= generic_delete_inode,
 	.show_options	= bpf_show_options,
-	.evict_inode	= bpf_evict_inode,
+	.free_inode	= bpf_free_inode,
 };
 
 enum {
 	OPT_MODE,
-	OPT_ERR,
 };
 
-static const match_table_t bpf_mount_tokens = {
-	{ OPT_MODE, "mode=%o" },
-	{ OPT_ERR, NULL },
+static const struct fs_parameter_spec bpf_param_specs[] = {
+	fsparam_u32oct	("mode",			OPT_MODE),
+	{}
+};
+
+static const struct fs_parameter_description bpf_fs_parameters = {
+	.name		= "bpf",
+	.specs		= bpf_param_specs,
 };
 
 struct bpf_mount_opts {
 	umode_t mode;
 };
 
-static int bpf_parse_options(char *data, struct bpf_mount_opts *opts)
+static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	substring_t args[MAX_OPT_ARGS];
-	int option, token;
-	char *ptr;
+	struct bpf_mount_opts *opts = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
 
-	opts->mode = S_IRWXUGO;
-
-	while ((ptr = strsep(&data, ",")) != NULL) {
-		if (!*ptr)
-			continue;
-
-		token = match_token(ptr, bpf_mount_tokens, args);
-		switch (token) {
-		case OPT_MODE:
-			if (match_octal(&args[0], &option))
-				return -EINVAL;
-			opts->mode = option & S_IALLUGO;
-			break;
+	opt = fs_parse(fc, &bpf_fs_parameters, param, &result);
+	if (opt < 0)
 		/* We might like to report bad mount options here, but
 		 * traditionally we've ignored all mount options, so we'd
 		 * better continue to ignore non-existing options for bpf.
 		 */
-		}
+		return opt == -ENOPARAM ? 0 : opt;
+
+	switch (opt) {
+	case OPT_MODE:
+		opts->mode = result.uint_32 & S_IALLUGO;
+		break;
 	}
 
 	return 0;
 }
 
-static int bpf_fill_super(struct super_block *sb, void *data, int silent)
+static int bpf_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	static const struct tree_descr bpf_rfiles[] = { { "" } };
-	struct bpf_mount_opts opts;
+	struct bpf_mount_opts *opts = fc->fs_private;
 	struct inode *inode;
 	int ret;
 
-	ret = bpf_parse_options(data, &opts);
-	if (ret)
-		return ret;
-
 	ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
 	if (ret)
 		return ret;
@@ -649,21 +639,50 @@
 	inode = sb->s_root->d_inode;
 	inode->i_op = &bpf_dir_iops;
 	inode->i_mode &= ~S_IALLUGO;
-	inode->i_mode |= S_ISVTX | opts.mode;
+	inode->i_mode |= S_ISVTX | opts->mode;
 
 	return 0;
 }
 
-static struct dentry *bpf_mount(struct file_system_type *type, int flags,
-				const char *dev_name, void *data)
+static int bpf_get_tree(struct fs_context *fc)
 {
-	return mount_nodev(type, flags, data, bpf_fill_super);
+	return get_tree_nodev(fc, bpf_fill_super);
+}
+
+static void bpf_free_fc(struct fs_context *fc)
+{
+	kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations bpf_context_ops = {
+	.free		= bpf_free_fc,
+	.parse_param	= bpf_parse_param,
+	.get_tree	= bpf_get_tree,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int bpf_init_fs_context(struct fs_context *fc)
+{
+	struct bpf_mount_opts *opts;
+
+	opts = kzalloc(sizeof(struct bpf_mount_opts), GFP_KERNEL);
+	if (!opts)
+		return -ENOMEM;
+
+	opts->mode = S_IRWXUGO;
+
+	fc->fs_private = opts;
+	fc->ops = &bpf_context_ops;
+	return 0;
 }
 
 static struct file_system_type bpf_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "bpf",
-	.mount		= bpf_mount,
+	.init_fs_context = bpf_init_fs_context,
+	.parameters	= &bpf_fs_parameters,
 	.kill_sb	= kill_litter_super,
 };