hi, i have attached the module. Can any one review it and tell me what was the problem in this. Basically, i am trying to write in a raw hard disk, i doubt in the blocknr and brsector value.
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#define MINORBITS 8 //these two macros are used to find b_rdev value
#define MKDEV(ma,mi) (((ma) << MINORBITS) | (mi))
#define SIZE 512
#define BLK_SIZE 512
#define SECTOR_SIZE 512
int dataWrite(void);
void ioCompleteHandler(struct buffer_head *bh, int uptodate);
int major_no;
struct block_device_operations block_bdops;
void ioCompleteHandler(struct buffer_head *bh, int uptodate)
{
printk(KERN_INFO"Freeing the memory in completeHandler function\n");
mark_buffer_uptodate(bh, uptodate);
kfree(bh->b_data);
kfree(bh);
printk(KERN_INFO"Memory freed in iocompleHandler function\n");
}
int dataWrite()
{
struct buffer_head *bh;
char *datpot;
printk(KERN_INFO" For testing\n");
printk(KERN_INFO"size of buffer is %d\n",sizeof(struct buffer_head));
bh=kmalloc(sizeof(struct buffer_head),GFP_KERNEL);
if( NULL == bh)
{
printk(KERN_INFO" kmalloc failed\n");
return -1 ;
}
bh->b_next = NULL;
bh->b_next_free = NULL;
bh->b_prev_free = NULL;
bh->b_this_page = NULL;
bh->b_reqnext = NULL;
bh->b_pprev = NULL;
set_bit (BH_Uptodate, &bh->b_state);
set_bit (BH_Mapped, &bh->b_state); //set if the device is mapped
set_bit (BH_Req, &bh->b_state);
set_bit (BH_Dirty, &bh->b_state); //added
bh->b_size=SIZE;
bh->b_dev = MKDEV(8,16);
bh->b_blocknr= 1; //not sure
bh->b_rsector = bh->b_blocknr * (BLK_SIZE/SECTOR_SIZE); // not sure
printk(KERN_INFO"allocating buffer the data\n");
datpot = kmalloc(SIZE,GFP_KERNEL);
if (NULL == datpot)
{
printk(KERN_INFO"data memory allocation failed\n");
return -1;
}
bh->b_data=datpot;
bh->b_page = virt_to_page(bh->b_data);
printk(KERN_INFO"virtual to page done\n");
bh->b_rdev= bh->b_dev;
bh->b_end_io=ioCompleteHandler;
// bh->b_private = bh;
printk(KERN_INFO"calling generic make request\n");
generic_make_request(WRITE,bh);
printk(KERN_INFO" write done\n");
return 0;
}
static int block_init(void)
{
int ret;
major_no = register_blkdev(0,"block_data",&block_bdops);
if ( major_no <0)
{
printk(KERN_INFO"Failed to register the module\n");
return -1;
}
printk(KERN_INFO"Block_data Module inserted\n");
ret = dataWrite();
return 0;
}
static void block_exit()
{
int ret;
ret = unregister_blkdev(major_no,"block_date");
if( ret < 0 )
{
printk(KERN_INFO"failed to unregister the module\n");
//return -1;
}
printk(KERN_INFO"Block_data Module removed\n");
}
module_init(block_init);
module_exit(block_exit);
MODULE_LICENSE("GPL");
--
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