最近在编写块设备驱动，使用制造请求队列函数时，set_bit()和bio_endio()函数报错，请问这是什么原因？
set_bit(BIO_UPTODATE, &bio->bi_flags);
bio_endio(bio, 0);
总体代码如下：
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/string.h>
#include <linux/irq.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/input/mt.h>
#include <linux/input/touchscreen.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>
/*参考例程*/
/*定义磁盘大小，内存模式*/
#define RAMDISK_SIZE (2 * 1024 * 1024) /*大小2MB*/
#define RAMDISK_NAME "ramdisk" /*名字*/
#define RAMDISK_MINOR 3 /*表示3个分区*/
/*ramdisk设备结构体*/
struct ramdisk_dev
{
int major; /*主设备号*/
unsigned char *ramdiskbuf; /*ramdisk的内存空间，模拟磁盘的空间*/
struct gendisk *gendisk;
struct request_queue *queue;
spinlock_t lock; /*自旋锁*/
};
struct ramdisk_dev ramdisk;
#if 0
/*具体的数据处理过程*/
static void ramdisk_transfer(struct request *req)
{
/*数据传输三要素：源，目的，长度。
*内存地址，块设备地址，长度
*/
unsigned long start = blk_rq_pos(req) << 9; /*blk_rq_pos获取到要操作的块设备扇区地址，左移9位，地址字节*/
unsigned long len = blk_rq_cur_bytes(req); /*数据长度*/
/*获取bio里面的缓冲区：
*如果是读：从磁盘里面读取到的数据保存在缓冲区里面
*如果是写：此缓冲区保存着要写入到磁盘里面的数据
*/
void *buffer = bio_data(req->bio);
if(rq_data_dir(req) == READ) /*读操作*/
memcpy(buffer, ramdisk.ramdiskbuf + start, len);
else /*写操作*/
memcpy(ramdisk.ramdiskbuf + start, buffer, len);
}
#endif
/*制造请求函数*/
static void ramdisk_make_request(struct request_queue *queue, struct bio *bio)
{
int offset;
struct bio_vec bvec;
struct bvec_iter iter;
unsigned long len = 0;
offset = bio->bi_iter.bi_sector << 9; /*要操作的磁盘起始扇区偏移,改为字节地址*/
/*循环处理每个段*/
bio_for_each_segment(bvec, bio, iter) {
/*获取bio里面的缓冲区：
*如果是读：从磁盘里面读取到的数据保存在缓冲区里面
*如果是写：此缓冲区保存着要写入到磁盘里面的数据
*/
char *ptr = page_address(bvec.bv_page) + bvec.bv_offset;
len = bvec.bv_len; /*长度*/
if(bio_data_dir(bio) == READ) /*读操作*/
memcpy(ptr, ramdisk.ramdiskbuf + offset, len);
else /*写操作*/
memcpy(ramdisk.ramdiskbuf + offset, ptr, len);
offset += len;
}
set_bit(BIO_UPTODATE, &bio->bi_flags);
bio_endio(bio, 0);
}
static int ramdisk_open(struct block_device *bdev, fmode_t mode)
{
printk("ramdisk_open\r\n");
return 0;
}
static void ramdisk_release(struct gendisk *disk, fmode_t mode)
{
printk("ramdisk_release\r\n");
}
static int ramdisk_getgeo(struct block_device *dev, struct hd_geometry *geo)
{
printk("ramdisk_getgeo\r\n");
/*硬盘信息*/
geo->heads = 2; /*磁头*/
geo->cylinders = 32; /*柱面，磁道*/
geo->sectors = RAMDISK_SIZE/(2 * 32 * 512); /*一个磁道里面的扇区数量*/
return 0;
}
/*块设备操作集*/
static const struct block_device_operations ramdisk_fops =
{
.owner = THIS_MODULE,
.open = ramdisk_open,
.release = ramdisk_release,
.getgeo = ramdisk_getgeo,
};
/* 驱动入口函数 */
static int __init ramdisk_init(void)
{
int ret = 0;
printk("ramdisk_init\r\n");
/*1.先申请内存*/
ramdisk.ramdiskbuf = kzalloc(RAMDISK_SIZE, GFP_KERNEL);
if(ramdisk.ramdiskbuf == NULL){
ret = -EINVAL;
goto ramalloc_fail;
}
/*2.注册块设备*/
ramdisk.major = register_blkdev(0,RAMDISK_NAME);
if(ramdisk.major < 0) {
ret = -EINVAL;
goto ramdisk_register_blkdev_fail;
}
printk("ramdisk major = %d\r\n", ramdisk.major);
/*3.申请gendisk*/
ramdisk.gendisk = alloc_disk(RAMDISK_MINOR);
if(!ramdisk.gendisk){
ret = -EINVAL;
goto gendisk_alloc_fail;
}
/*4.初始化自旋锁*/
spin_lock_init(&ramdisk.lock);
/*5.申请请求队列*/
ramdisk.queue = blk_alloc_queue(GFP_KERNEL);
if(!ramdisk.queue){
ret = -EINVAL;
goto blk_queue_fail;
}
/*绑定"制造请求"函数*/
blk_queue_make_request(ramdisk.queue, ramdisk_make_request);
/*6.初始化gendisk*/
ramdisk.gendisk->major = ramdisk.major; /*主设备号*/
ramdisk.gendisk->first_minor = 0;
ramdisk.gendisk->fops = &ramdisk_fops;
ramdisk.gendisk->private_data = &ramdisk;
ramdisk.gendisk->queue = ramdisk.queue;
sprintf(ramdisk.gendisk->disk_name, RAMDISK_NAME);
set_capacity(ramdisk.gendisk, RAMDISK_SIZE/512); /*设置gendisk容量，单位扇区*/
add_disk(ramdisk.gendisk);
return 0;
blk_queue_fail:
put_disk(ramdisk.gendisk);
gendisk_alloc_fail:
unregister_blkdev(ramdisk.major, RAMDISK_NAME);
ramdisk_register_blkdev_fail:
kfree(ramdisk.ramdiskbuf);
ramalloc_fail:
return ret;
}
/* 驱动出口函数 */
static void __exit ramdisk_exit(void)
{
printk("ramdisk exit\r\n");
del_gendisk(ramdisk.gendisk);
put_disk(ramdisk.gendisk);
blk_cleanup_queue(ramdisk.queue);
unregister_blkdev(ramdisk.major, RAMDISK_NAME);
kfree(ramdisk.ramdiskbuf);
}
module_init(ramdisk_init);
module_exit(ramdisk_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("ty");
具体报错如下：
make -C /home/user/linux/rv/kernel M=/home/user/linux/study/ramdisk_makerequest ARCH=arm CROSS_COMPILE=/home/user/linux/rv/prebuilts/gcc/linux-x86/arm/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/bin/arm-linux-gnueabihf- modules
make[1]: 进入目录“/home/user/linux/rv/kernel”
CC [M] /home/user/linux/study/ramdisk_makerequest/ramdisk.o
In file included from ./include/linux/bitops.h:19,
from ./include/linux/kernel.h:11,
from ./include/linux/list.h:9,
from ./include/linux/module.h:9,
from /home/user/linux/study/ramdisk_makerequest/ramdisk.c:1:
/home/user/linux/study/ramdisk_makerequest/ramdisk.c: In function 'ramdisk_make_request':
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:98:13: error: 'BIO_UPTODATE' undeclared (first use in this function); did you mean 'IS_PRIVATE'?
set_bit(BIO_UPTODATE, &bio->bi_flags);
^~~~~~~~~~~~
./arch/arm/include/asm/bitops.h:183:42: note: in definition of macro 'ATOMIC_BITOP'
#define ATOMIC_BITOP(name,nr,p) _##name(nr,p)
^~
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:98:5: note: in expansion of macro 'set_bit'
set_bit(BIO_UPTODATE, &bio->bi_flags);
^~~~~~~
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:98:13: note: each undeclared identifier is reported only once for each function it appears in
set_bit(BIO_UPTODATE, &bio->bi_flags);
^~~~~~~~~~~~
./arch/arm/include/asm/bitops.h:183:42: note: in definition of macro 'ATOMIC_BITOP'
#define ATOMIC_BITOP(name,nr,p) _##name(nr,p)
^~
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:98:5: note: in expansion of macro 'set_bit'
set_bit(BIO_UPTODATE, &bio->bi_flags);
^~~~~~~
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:98:29: error: passing argument 2 of '_set_bit' from incompatible pointer type [-Werror=incompatible-pointer-types]
set_bit(BIO_UPTODATE, &bio->bi_flags);
^~~~~~~~~~~~~~
./arch/arm/include/asm/bitops.h:183:45: note: in definition of macro 'ATOMIC_BITOP'
#define ATOMIC_BITOP(name,nr,p) _##name(nr,p)
^
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:98:5: note: in expansion of macro 'set_bit'
set_bit(BIO_UPTODATE, &bio->bi_flags);
^~~~~~~
./arch/arm/include/asm/bitops.h:153:55: note: expected 'volatile long unsigned int *' but argument is of type 'short unsigned int *'
extern void _set_bit(int nr, volatile unsigned long * p);
~~~~~~~~~~~~~~~~~~~~~~~~~^
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:99:5: error: too many arguments to function 'bio_endio'
bio_endio(bio, 0);
^~~~~~~~~
In file included from ./include/linux/blkdev.h:21,
from /home/user/linux/study/ramdisk_makerequest/ramdisk.c:26:
./include/linux/bio.h:448:13: note: declared here
extern void bio_endio(struct bio *);
^~~~~~~~~
/home/user/linux/study/ramdisk_makerequest/ramdisk.c: In function 'ramdisk_init':
/home/user/linux/study/ramdisk_makerequest/ramdisk.c:172:41: error: passing argument 2 of 'blk_queue_make_request' from incompatible pointer type [-Werror=incompatible-pointer-types]
blk_queue_make_request(ramdisk.queue, ramdisk_make_request);
^~~~~~~~~~~~~~~~~~~~
In file included from /home/user/linux/study/ramdisk_makerequest/ramdisk.c:26:
./include/linux/blkdev.h:1206:60: note: expected 'blk_qc_t (*)(struct request_queue *, struct bio *)' {aka 'unsigned int (*)(struct request_queue *, struct bio *)'} but argument is of type 'void (*)(struct request_queue *, struct bio *)'
extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
^~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
scripts/Makefile.build:339: recipe for target '/home/user/linux/study/ramdisk_makerequest/ramdisk.o' failed
make[2]: *** [/home/user/linux/study/ramdisk_makerequest/ramdisk.o] Error 1
Makefile:1641: recipe for target '_module_/home/user/linux/study/ramdisk_makerequest' failed
make[1]: *** [_module_/home/user/linux/study/ramdisk_makerequest] Error 2
make[1]: 离开目录“/home/user/linux/rv/kernel”
Makefile:12: recipe for target 'all' failed
make: *** [all] Error 2
