下面是一个示例代码,展示了如何使用block_device
和BIO来进行NVMe设备的读写操作:
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#define NVME_DEVICE_NAME "nvme0n1"
struct block_device *bdev;
char buffer[512];
static void bio_complete(struct bio *bio, int error)
{
if (error) {
printk(KERN_ERR "I/O error: %d\n", error);
} else {
printk(KERN_INFO "I/O completed successfully.\n");
}
bio_endio(bio);
}
static void nvme_read_block(unsigned long sector)
{
struct bio *bio;
bio = bio_alloc(GFP_KERNEL, 1);
if (!bio) {
printk(KERN_ERR "Failed to allocate BIO.\n");
return;
}
bio->bi_iter.bi_sector = sector;
bio->bi_bdev = bdev;
bio_set_dev(bio, bdev->bd_disk);
bio_add_page(bio, virt_to_page(buffer), PAGE_SIZE, 0);
bio->bi_end_io = bio_complete;
submit_bio_read(bio);
}
static void nvme_write_block(unsigned long sector)
{
struct page *page;
struct bio *bio;
page = virt_to_page(buffer);
bio = bio_alloc(GFP_KERNEL, 1);
if (!bio) {
printk(KERN_ERR "Failed to allocate BIO.\n");
return;
}
bio->bi_iter.bi_sector = sector;
bio->bi_bdev = bdev;
bio_set_dev(bio, bdev->bd_disk);
bio_add_page(bio, page, PAGE_SIZE, 0);
bio->bi_end_io = bio_complete;
submit_bio_write(bio);
}
static int __init nvme_demo_init(void)
{
struct block_device *bdev_temp;
bdev_temp = blkdev_get_by_path("/dev/" NVME_DEVICE_NAME, FMODE_READ | FMODE_WRITE, NULL);
if (IS_ERR(bdev_temp)) {
printk(KERN_ERR "Failed to open block device: %s\n", NVME_DEVICE_NAME);
return PTR_ERR(bdev_temp);
}
bdev = bdget_disk(bdev_temp->bd_disk, 0);
if (!bdev) {
printk(KERN_ERR "Failed to get block device.\n");
blkdev_put(bdev_temp, FMODE_READ | FMODE_WRITE);
return -ENODEV;
}
strcpy(buffer, "Hello World!");
nvme_write_block(0); // 写入第一个扇区
memset(buffer, 0, sizeof(buffer)); // 清空缓冲区
nvme_read_block(0); // 读取第一个扇区
return 0;
}
static void __exit nvme_demo_exit(void)
{
if (bdev)
bdput(bdev);
printk(KERN_INFO "NVMe demo module unloaded.\n");
}
module_init(nvme_demo_init);
module_exit(nvme_demo_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
请注意,此示例仅用于展示基本的NVMe设备读写操作。实际情况中,还需要进行错误处理、边界检查等。
在模块初始化期间,我们通过blkdev_get_by_path()
打开指定的块设备,并通过bdget_disk()
获取相应的block_device
结构体。然后,我们将一个字符串写入第一个扇区,并通过nvme_write_block()
函数进行写操作。
接着,我们清空缓冲区并使用nvme_read_block()
函数来读取第一个扇区的内容。
需要注意的是,本示例代码仅用于说明目的,实际情况中可能需要更复杂的错误处理、边界检查和数据验证等。同时,请确保在运行此示例代码之前备份好重要的数据,以防意外情况发生。
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