Linux内核中kfifo使用
2015-06-17 18:02
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/* * Sample kfifo byte stream implementation * * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net> * * Released under the GPL version 2 only. * */ #include <linux/init.h> #include <linux/module.h> #include <linux/proc_fs.h> #include <linux/mutex.h> #include <linux/kfifo.h> #include <linux/kthread.h> #include <linux/time.h> #include <linux/delay.h> /* * This module shows how to create a byte stream fifo. */ /* fifo size in elements (bytes) */ #define FIFO_SIZE 32 /* name of the proc entry */ #define PROC_FIFO "bytestream-fifo" /* lock for procfs read access */ static DEFINE_MUTEX(read_lock); /* lock for procfs write access */ static DEFINE_MUTEX(write_lock); /* * define DYNAMIC in this example for a dynamically allocated fifo. * * Otherwise the fifo storage will be a part of the fifo structure. */ #if 1 #define DYNAMIC #endif #ifdef DYNAMIC static struct kfifo test; #else static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE); #endif static const unsigned char expected_result[FIFO_SIZE] = { 3, 4, 5, 6, 7, 8, 9, 0, 1, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, }; static int __init testfunc(void) { unsigned char buf[32]={'0'}; unsigned char i, j; unsigned int ret; printk(KERN_INFO "byte stream fifo test start\n"); if(!kfifo_is_empty(&test)){ printk(KERN_INFO"1111not empty \n!"); }else{ printk(KERN_INFO "empty ! \n"); } /* put string into the fifo */ kfifo_in(&test, "hello",5); /* get max of 2 elements from the fifo */ ret = kfifo_in(&test, "121212121212121212121212121212121212",36); printk(KERN_INFO "ret: %d buf = %s\n" , ret,buf); if(!kfifo_is_full(&test)){ printk(KERN_INFO"2222not kfifo_is_full \n!"); }else{ printk(KERN_INFO "kfifo_is_full ! \n"); } /* and put it back to the end of the fifo */ ret = kfifo_out(&test,buf,9); printk(KERN_INFO "ret: %d buf = %s\n", ret,buf); if(!kfifo_is_empty(&test)){ printk(KERN_INFO"2222not empty ! \n"); }else{ printk(KERN_INFO "empty ! \n"); } memset(buf,0,32); ret = kfifo_out(&test,buf,8); printk(KERN_INFO "test passed buf = %s\n",buf); memset(buf,0,32); ret = kfifo_out(&test,buf,8); printk(KERN_INFO "test passed buf = %s\n",buf); if(!kfifo_is_empty(&test)){ printk(KERN_INFO "3333333333not empty ! \n"); }else{ printk(KERN_INFO "empty ! \n"); } return 0; } static ssize_t fifo_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { int ret; unsigned int copied; if (mutex_lock_interruptible(&write_lock)) return -ERESTARTSYS; ret = kfifo_from_user(&test, buf, count, &copied); mutex_unlock(&write_lock); return ret ? ret : copied; } static ssize_t fifo_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int ret; unsigned int copied; if (mutex_lock_interruptible(&read_lock)) return -ERESTARTSYS; ret = kfifo_to_user(&test, buf, count, &copied); mutex_unlock(&read_lock); return ret ? ret : copied; } static const struct file_operations fifo_fops = { .owner = THIS_MODULE, .read = fifo_read, .write = fifo_write, .llseek = noop_llseek, }; static int productor_thread(void *p){ unsigned char mac[7]={0x00}; int i = 0; unsigned int ret; while(i<100){ mac[0] = i; mac[1] = i+1; mac[2] = i+2; mac[3] = i+3; mac[4] = i+4; mac[5] = i+5; mac[6] = i+6; ret = kfifo_in(&test,mac,7); i++; msleep(1000); } return 0; } static int consumer_thread(void *p){ unsigned char mac[7]={0x00}; unsigned int ret; int i = 0; while(i<10){ ret = kfifo_out(&test,mac,7); msleep(1000); if(kfifo_is_empty(&test)){ i++; }else{ printk(KERN_INFO "mac =0x%x:0x%x:0x%x:0x%x:0x%x:0x%x:0x%x \n",mac[0],mac[1],mac[2],mac[3],mac[4],mac[5],mac[6]); } } printk("iiiiiiiiiiiiiiiiiiiiiiii=%d \n",i); return 0; } static struct task_struct *ps_tsks1; static struct task_struct *ps_tsks2; static int __init example_init(void) { #ifdef DYNAMIC int ret; ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL); if (ret) { printk(KERN_ERR "error kfifo_alloc\n"); return ret; } #else INIT_KFIFO(test); #endif ps_tsks1 = kthread_run(productor_thread,(void *)(unsigned long)NULL,"productor_thread"); ps_tsks2 = kthread_run(consumer_thread,(void *)(unsigned long)NULL,"consumer_thread"); /* if (testfunc() < 0) { #ifdef DYNAMIC kfifo_free(&test); #endif return -EIO; } */ if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) { #ifdef DYNAMIC kfifo_free(&test); #endif return -ENOMEM; } return 0; } static void __exit example_exit(void) { //kthread_stop(ps_tsks1); //kthread_stop(ps_tsks2); remove_proc_entry(PROC_FIFO, NULL); #ifdef DYNAMIC kfifo_free(&test); #endif } module_init(example_init); module_exit(example_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");
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