/*
 *  Linux内核诊断工具--工具通用调试缓冲区模块
 *  这是为了解决procfs/trace的问题而编写
 *
 * Copyright (C) 2020 Alibaba Ltd.
 *
 * 作者： Baoyou Xie <baoyou.xie@linux.alibaba.com>
 *
 * License terms: GNU General Public License (GPL) version 3
 */

#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>

#define DIAG_VARIANT_BUFFER_HEAD_MAGIC_SEALED 197612031122
#define DIAG_VARIANT_BUFFER_HEAD_MAGIC_UNSEALED 197612031234

struct diag_variant_buffer_head {
  unsigned long magic;
  unsigned long len;
};

struct diag_variant_buffer {
  struct {
    char *data;
    unsigned int pos;
    struct diag_variant_buffer_head *head;
  } buffers[2];
  /* 0 or 1 */
  int buffer_toggle;

  struct {
    char *data;
    unsigned int len;
  } product;

  unsigned int buf_size;
  unsigned int alloced;
  spinlock_t lock;
  struct mutex mutex;
};

#define diag_variant_buffer_spin_lock(__buffer, flags)                         \
  spin_lock_irqsave(&((__buffer)->lock), flags)
#define diag_variant_buffer_spin_unlock(__buffer, flags)                       \
  spin_unlock_irqrestore(&((__buffer)->lock), flags)
int init_diag_variant_buffer(struct diag_variant_buffer *buffer,
                             unsigned int buf_size);
int alloc_diag_variant_buffer(struct diag_variant_buffer *buffer);
void destroy_diag_variant_buffer(struct diag_variant_buffer *buffer);
void discard_diag_variant_buffer(struct diag_variant_buffer *buffer);
void backup_diag_variant_buffer(struct diag_variant_buffer *buffer);
asmlinkage int diag_variant_buffer_reserve(struct diag_variant_buffer *buffer,
                                           size_t len);
asmlinkage int diag_variant_buffer_seal(struct diag_variant_buffer *buffer);
asmlinkage int
diag_variant_buffer_write_nolock(struct diag_variant_buffer *buffer,
                                 const void *data, size_t len);
void diag_variant_buffer_mutex_lock(struct diag_variant_buffer *buffer);
void diag_variant_buffer_mutex_unlock(struct diag_variant_buffer *buffer);
int copy_to_user_variant_buffer(struct diag_variant_buffer *variant_buffer,
                                void __user *ptr_len, void __user *buf,
                                size_t size);