18 内核开发-内核重点数据结构学习

课程简介：
Linux内核开发入门是一门旨在帮助学习者从最基本的知识开始学习Linux内核开发的入门课程。该课程旨在为对Linux内核开发感兴趣的初学者提供一个扎实的基础，让他们能够理解和参与到Linux内核的开发过程中。

课程特点：
1. 入门级别：该课程专注于为初学者提供Linux内核开发的入门知识。无论你是否具有编程或操作系统的背景，该课程都将从最基本的概念和技术开始，逐步引导学习者深入了解Linux内核开发的核心原理。

2. 系统化学习：课程内容经过系统化的安排，涵盖了Linux内核的基础知识、内核模块编程、设备驱动程序开发等关键主题。学习者将逐步了解Linux内核的结构、功能和工作原理，并学习如何编写和调试内核模块和设备驱动程序。

3. 实践导向：该课程强调实践，通过丰富的实例和编程练习，帮助学习者将理论知识应用到实际的Linux内核开发中。学习者将有机会编写简单的内核模块和设备驱动程序，并通过实际的测试和调试来加深对Linux内核开发的理解。

4. 配套资源：为了帮助学习者更好地掌握课程内容，该课程提供了丰富的配套资源，包括教学文档、示例代码、实验指导和参考资料等。学习者可以根据自己的学习进度和需求，灵活地利用这些资源进行学习和实践。

无论你是计算机科学专业的学生、软件工程师还是对Linux内核开发感兴趣的爱好者，Linux内核开发入门课程都将为你提供一个扎实的学习平台，帮助你掌握Linux内核开发的基础知识，为进一步深入研究和应用Linux内核打下坚实的基础。

这一讲，主要分享内核中的重点数据结构，并且以脑图的形式进行整理，后面如果有其他内核数据结构，会一同整理到这里。主要介绍内核中使用的4大数据结构：链表，队列，映射，二叉树。

以下是脑图主要内容。

需要脑图文件的可以私信或者评论留言，可以免费同步给你。文章后再贴下 list.h kfifo.h 相关文件定义

LXR linux/include/linux/klist.h

  1/*
  2 *      klist.h - Some generic list helpers, extending struct list_head a bit.
  3 *
  4 *      Implementations are found in lib/klist.c
  5 *
  6 *
  7 *      Copyright (C) 2005 Patrick Mochel
  8 *
  9 *      This file is rleased under the GPL v2.
  10 */
  11
  12#ifndef _LINUX_KLIST_H
  13#define _LINUX_KLIST_H
  14
  15#include <linux/spinlock.h>
  16#include <linux/completion.h>
  17#include <linux/kref.h>
  18#include <linux/list.h>
  19
  20struct klist_node;
  21struct klist {
  22        spinlock_t              k_lock;
  23        struct list_head        k_list;
  24        void                    (*get)(struct klist_node *);
  25        void                    (*put)(struct klist_node *);
  26};
  27
  28
  29extern void klist_init(struct klist * k, void (*get)(struct klist_node *),
  30                       void (*put)(struct klist_node *));
  31
  32struct klist_node {
  33        struct klist            * n_klist;
  34        struct list_head        n_node;
  35        struct kref             n_ref;
  36        struct completion       n_removed;
  37};
  38
  39extern void klist_add_tail(struct klist_node * n, struct klist * k);
  40extern void klist_add_head(struct klist_node * n, struct klist * k);
  41
  42extern void klist_del(struct klist_node * n);
  43extern void klist_remove(struct klist_node * n);
  44
  45extern int klist_node_attached(struct klist_node * n);
  46
  47
  48struct klist_iter {
  49        struct klist            * i_klist;
  50        struct list_head        * i_head;
  51        struct klist_node       * i_cur;
  52};
  53
  54
  55extern void klist_iter_init(struct klist * k, struct klist_iter * i);
  56extern void klist_iter_init_node(struct klist * k, struct klist_iter * i, 
  57                                 struct klist_node * n);
  58extern void klist_iter_exit(struct klist_iter * i);
  59extern struct klist_node * klist_next(struct klist_iter * i);
  60
  61#endif
  62

The original LXR software by the LXR community, this experimental version by lxr@linux.no.

LXR linux/include/linux/kfifo.h

  1/*
  2 * A simple kernel FIFO implementation.
  3 *
  4 * Copyright (C) 2004 Stelian Pop <stelian@popies.net>
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License as published by
  8 * the Free Software Foundation; either version 2 of the License, or
  9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 *
  20 */
  21#ifndef _LINUX_KFIFO_H
  22#define _LINUX_KFIFO_H
  23
  24#ifdef __KERNEL__
  25
  26#include <linux/kernel.h>
  27#include <linux/spinlock.h>
  28
  29struct kfifo {
  30        unsigned char *buffer;  /* the buffer holding the data */
  31        unsigned int size;      /* the size of the allocated buffer */
  32        unsigned int in;        /* data is added at offset (in % size) */
  33        unsigned int out;       /* data is extracted from off. (out % size) */
  34        spinlock_t *lock;       /* protects concurrent modifications */
  35};
  36
  37extern struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size,
  38                                gfp_t gfp_mask, spinlock_t *lock);
  39extern struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask,
  40                                 spinlock_t *lock);
  41extern void kfifo_free(struct kfifo *fifo);
  42extern unsigned int __kfifo_put(struct kfifo *fifo,
  43                                unsigned char *buffer, unsigned int len);
  44extern unsigned int __kfifo_get(struct kfifo *fifo,
  45                                unsigned char *buffer, unsigned int len);
  46
  47/**
  48 * __kfifo_reset - removes the entire FIFO contents, no locking version
  49 * @fifo: the fifo to be emptied.
  50 */
  51static inline void __kfifo_reset(struct kfifo *fifo)
  52{
  53        fifo->in = fifo->out = 0;
  54}
  55
  56/**
  57 * kfifo_reset - removes the entire FIFO contents
  58 * @fifo: the fifo to be emptied.
  59 */
  60static inline void kfifo_reset(struct kfifo *fifo)
  61{
  62        unsigned long flags;
  63
  64        spin_lock_irqsave(fifo->lock, flags);
  65
  66        __kfifo_reset(fifo);
  67
  68        spin_unlock_irqrestore(fifo->lock, flags);
  69}
  70
  71/**
  72 * kfifo_put - puts some data into the FIFO
  73 * @fifo: the fifo to be used.
  74 * @buffer: the data to be added.
  75 * @len: the length of the data to be added.
  76 *
  77 * This function copies at most 'len' bytes from the 'buffer' into
  78 * the FIFO depending on the free space, and returns the number of
  79 * bytes copied.
  80 */
  81static inline unsigned int kfifo_put(struct kfifo *fifo,
  82                                     unsigned char *buffer, unsigned int len)
  83{
  84        unsigned long flags;
  85        unsigned int ret;
  86
  87        spin_lock_irqsave(fifo->lock, flags);
  88
  89        ret = __kfifo_put(fifo, buffer, len);
  90
  91        spin_unlock_irqrestore(fifo->lock, flags);
  92
  93        return ret;
  94}
  95
  96/**
  97 * kfifo_get - gets some data from the FIFO
  98 * @fifo: the fifo to be used.
  99 * @buffer: where the data must be copied.
 100 * @len: the size of the destination buffer.
 101 *
 102 * This function copies at most 'len' bytes from the FIFO into the
 103 * 'buffer' and returns the number of copied bytes.
 104 */
 105static inline unsigned int kfifo_get(struct kfifo *fifo,
 106                                     unsigned char *buffer, unsigned int len)
 107{
 108        unsigned long flags;
 109        unsigned int ret;
 110
 111        spin_lock_irqsave(fifo->lock, flags);
 112
 113        ret = __kfifo_get(fifo, buffer, len);
 114
 115        /*
 116         * optimization: if the FIFO is empty, set the indices to 0
 117         * so we don't wrap the next time
 118         */
 119        if (fifo->in == fifo->out)
 120                fifo->in = fifo->out = 0;
 121
 122        spin_unlock_irqrestore(fifo->lock, flags);
 123
 124        return ret;
 125}
 126
 127/**
 128 * __kfifo_len - returns the number of bytes available in the FIFO, no locking version
 129 * @fifo: the fifo to be used.
 130 */
 131static inline unsigned int __kfifo_len(struct kfifo *fifo)
 132{
 133        return fifo->in - fifo->out;
 134}
 135
 136/**
 137 * kfifo_len - returns the number of bytes available in the FIFO
 138 * @fifo: the fifo to be used.
 139 */
 140static inline unsigned int kfifo_len(struct kfifo *fifo)
 141{
 142        unsigned long flags;
 143        unsigned int ret;
 144
 145        spin_lock_irqsave(fifo->lock, flags);
 146
 147        ret = __kfifo_len(fifo);
 148
 149        spin_unlock_irqrestore(fifo->lock, flags);
 150
 151        return ret;
 152}
 153
 154#else
 155#warning "don't include kernel headers in userspace"
 156#endif /* __KERNEL__ */
 157#endif
 158