v4.19.13 snapshot.
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
new file mode 100644
index 0000000..a121982
--- /dev/null
+++ b/include/linux/seq_file.h
@@ -0,0 +1,244 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SEQ_FILE_H
+#define _LINUX_SEQ_FILE_H
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/bug.h>
+#include <linux/mutex.h>
+#include <linux/cpumask.h>
+#include <linux/nodemask.h>
+#include <linux/fs.h>
+#include <linux/cred.h>
+
+struct seq_operations;
+
+struct seq_file {
+ char *buf;
+ size_t size;
+ size_t from;
+ size_t count;
+ size_t pad_until;
+ loff_t index;
+ loff_t read_pos;
+ u64 version;
+ struct mutex lock;
+ const struct seq_operations *op;
+ int poll_event;
+ const struct file *file;
+ void *private;
+};
+
+struct seq_operations {
+ void * (*start) (struct seq_file *m, loff_t *pos);
+ void (*stop) (struct seq_file *m, void *v);
+ void * (*next) (struct seq_file *m, void *v, loff_t *pos);
+ int (*show) (struct seq_file *m, void *v);
+};
+
+#define SEQ_SKIP 1
+
+/**
+ * seq_has_overflowed - check if the buffer has overflowed
+ * @m: the seq_file handle
+ *
+ * seq_files have a buffer which may overflow. When this happens a larger
+ * buffer is reallocated and all the data will be printed again.
+ * The overflow state is true when m->count == m->size.
+ *
+ * Returns true if the buffer received more than it can hold.
+ */
+static inline bool seq_has_overflowed(struct seq_file *m)
+{
+ return m->count == m->size;
+}
+
+/**
+ * seq_get_buf - get buffer to write arbitrary data to
+ * @m: the seq_file handle
+ * @bufp: the beginning of the buffer is stored here
+ *
+ * Return the number of bytes available in the buffer, or zero if
+ * there's no space.
+ */
+static inline size_t seq_get_buf(struct seq_file *m, char **bufp)
+{
+ BUG_ON(m->count > m->size);
+ if (m->count < m->size)
+ *bufp = m->buf + m->count;
+ else
+ *bufp = NULL;
+
+ return m->size - m->count;
+}
+
+/**
+ * seq_commit - commit data to the buffer
+ * @m: the seq_file handle
+ * @num: the number of bytes to commit
+ *
+ * Commit @num bytes of data written to a buffer previously acquired
+ * by seq_buf_get. To signal an error condition, or that the data
+ * didn't fit in the available space, pass a negative @num value.
+ */
+static inline void seq_commit(struct seq_file *m, int num)
+{
+ if (num < 0) {
+ m->count = m->size;
+ } else {
+ BUG_ON(m->count + num > m->size);
+ m->count += num;
+ }
+}
+
+/**
+ * seq_setwidth - set padding width
+ * @m: the seq_file handle
+ * @size: the max number of bytes to pad.
+ *
+ * Call seq_setwidth() for setting max width, then call seq_printf() etc. and
+ * finally call seq_pad() to pad the remaining bytes.
+ */
+static inline void seq_setwidth(struct seq_file *m, size_t size)
+{
+ m->pad_until = m->count + size;
+}
+void seq_pad(struct seq_file *m, char c);
+
+char *mangle_path(char *s, const char *p, const char *esc);
+int seq_open(struct file *, const struct seq_operations *);
+ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
+loff_t seq_lseek(struct file *, loff_t, int);
+int seq_release(struct inode *, struct file *);
+int seq_write(struct seq_file *seq, const void *data, size_t len);
+
+__printf(2, 0)
+void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
+__printf(2, 3)
+void seq_printf(struct seq_file *m, const char *fmt, ...);
+void seq_putc(struct seq_file *m, char c);
+void seq_puts(struct seq_file *m, const char *s);
+void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
+ unsigned long long num, unsigned int width);
+void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
+ unsigned long long num);
+void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
+void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
+ unsigned long long v, unsigned int width);
+
+void seq_escape(struct seq_file *m, const char *s, const char *esc);
+
+void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
+ int rowsize, int groupsize, const void *buf, size_t len,
+ bool ascii);
+
+int seq_path(struct seq_file *, const struct path *, const char *);
+int seq_file_path(struct seq_file *, struct file *, const char *);
+int seq_dentry(struct seq_file *, struct dentry *, const char *);
+int seq_path_root(struct seq_file *m, const struct path *path,
+ const struct path *root, const char *esc);
+
+int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
+int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
+int single_release(struct inode *, struct file *);
+void *__seq_open_private(struct file *, const struct seq_operations *, int);
+int seq_open_private(struct file *, const struct seq_operations *, int);
+int seq_release_private(struct inode *, struct file *);
+
+#define DEFINE_SHOW_ATTRIBUTE(__name) \
+static int __name ## _open(struct inode *inode, struct file *file) \
+{ \
+ return single_open(file, __name ## _show, inode->i_private); \
+} \
+ \
+static const struct file_operations __name ## _fops = { \
+ .owner = THIS_MODULE, \
+ .open = __name ## _open, \
+ .read = seq_read, \
+ .llseek = seq_lseek, \
+ .release = single_release, \
+}
+
+static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
+{
+#ifdef CONFIG_USER_NS
+ return seq->file->f_cred->user_ns;
+#else
+ extern struct user_namespace init_user_ns;
+ return &init_user_ns;
+#endif
+}
+
+/**
+ * seq_show_options - display mount options with appropriate escapes.
+ * @m: the seq_file handle
+ * @name: the mount option name
+ * @value: the mount option name's value, can be NULL
+ */
+static inline void seq_show_option(struct seq_file *m, const char *name,
+ const char *value)
+{
+ seq_putc(m, ',');
+ seq_escape(m, name, ",= \t\n\\");
+ if (value) {
+ seq_putc(m, '=');
+ seq_escape(m, value, ", \t\n\\");
+ }
+}
+
+/**
+ * seq_show_option_n - display mount options with appropriate escapes
+ * where @value must be a specific length.
+ * @m: the seq_file handle
+ * @name: the mount option name
+ * @value: the mount option name's value, cannot be NULL
+ * @length: the length of @value to display
+ *
+ * This is a macro since this uses "length" to define the size of the
+ * stack buffer.
+ */
+#define seq_show_option_n(m, name, value, length) { \
+ char val_buf[length + 1]; \
+ strncpy(val_buf, value, length); \
+ val_buf[length] = '\0'; \
+ seq_show_option(m, name, val_buf); \
+}
+
+#define SEQ_START_TOKEN ((void *)1)
+/*
+ * Helpers for iteration over list_head-s in seq_files
+ */
+
+extern struct list_head *seq_list_start(struct list_head *head,
+ loff_t pos);
+extern struct list_head *seq_list_start_head(struct list_head *head,
+ loff_t pos);
+extern struct list_head *seq_list_next(void *v, struct list_head *head,
+ loff_t *ppos);
+
+/*
+ * Helpers for iteration over hlist_head-s in seq_files
+ */
+
+extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
+ loff_t pos);
+extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
+ loff_t pos);
+extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
+ loff_t *ppos);
+
+extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
+ loff_t pos);
+extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
+ loff_t pos);
+extern struct hlist_node *seq_hlist_next_rcu(void *v,
+ struct hlist_head *head,
+ loff_t *ppos);
+
+/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
+extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
+
+extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
+
+void seq_file_init(void);
+#endif