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/*
* buffer.c ³ÌÐòÓÃÓÚ¶Ô¸ßËÙ»º³åÇø(³Ø)½øÐвÙ×÷ºÍ¹ÜÀí¡£¸ßËÙ»º³å
* ÇøÎ»ÓÚÄں˴úÂëºÍÖ÷ÄÚ´æÇøÖ®¼ä¡£
*
* |---|---|------------------|---------------------|-------------------|
* | | | * * * | buffer | |
* |---|---|------------------|---------------------|-------------------|
* | /|\
* |------------------------------------|
* \|/
* buffer_head (list)
*/
/*
* linux/fs/buffer.c
*
* (C) 1991 Linus Torvalds
*/
/*
* 'buffer.c' implements the buffer-cache functions. Race-conditions have
* been avoided by NEVER letting a interrupt change a buffer (except for the
* data, of course), but instead letting the caller do it. NOTE! As interrupts
* can wake up a caller, some cli-sti sequences are needed to check for
* sleep-on-calls. These should be extremely quick, though (I hope).
*/
/*
* NOTE! There is one discordant note here: checking floppies for
* disk change. This is where it fits best, I think, as it should
* invalidate changed floppy-disk-caches.
*/
#include <stdarg.h>
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <asm/system.h>
#include <asm/io.h>
extern int end; // ÓÉÁ¬½Ó³ÌÐòld Éú³ÉµÄ±íÃ÷³ÌÐòÄ©¶ËµÄ±äÁ¿£¬´ú±íµÄÊÇÒ»¸öÄÚ´æµØÖ·
struct buffer_head * start_buffer = (struct buffer_head *) &end;
struct buffer_head * hash_table[NR_HASH];
static struct buffer_head * free_list;
static struct task_struct * buffer_wait = NULL;
int NR_BUFFERS = 0;
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/*
* linux/fs/char_dev.c
*
* (C) 1991 Linus Torvalds
*/
#include <errno.h>
#include <sys/types.h> // ¶¨ÒåÁË»ù±¾µÄϵͳÊý¾ÝÀàÐÍ
#include <linux/sched.h>
#include <linux/kernel.h> // º¬ÓÐһЩÄں˳£Óú¯ÊýµÄÔÐζ¨Òå
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