Hello,
I want to provide an own ioctl in a block_device. Therefor I added my own ioctl-function in a gendisk. For testing I used a simple ramdisk found in one of the books I use to learn:
#include <linux/fs.h> #include <linux/module.h> #include <linux/init.h> #include <linux/blkdev.h>
#define BD_MAJOR 242 #define SIZE_IN_KBYTES 256
MODULE_LICENSE("GPL");static struct gendisk *disk; static struct request_queue *bdqueue; static char *mempool; static spinlock_t bdlock = SPIN_LOCK_UNLOCKED;
static void bd_request( request_queue_t *q )
{
[...]
}static int
myioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
printk(KERN_ALERT "ioctl was called\n");
if (cmd == 3249)
return 42;
return -ENOTTY;
}static struct block_device_operations bdops = {
.owner = THIS_MODULE,
.ioctl = myioctl,
};static int __init mod_init(void)
{
if (register_blkdev(BD_MAJOR, "bdsample" )) {
printk("blockdevice: Majornummer %d not free.",
BD_MAJOR);
return -EIO;
}
if( !(mempool=vmalloc(SIZE_IN_KBYTES*1024)) ) {
printk("vmalloc failed ...\n");
goto out_no_mem;
}if( !(disk=alloc_disk(1)) ) {
printk("alloc_disk failed ...\n");
goto out;
}
disk->major = BD_MAJOR;
disk->first_minor = 0;
if( (bdqueue=blk_init_queue(&bd_request,&bdlock))==NULL )
goto out;
blk_queue_hardsect_size( bdqueue, 512 );
disk->queue = bdqueue;
sprintf(disk->disk_name, "bd0");
set_capacity( disk, (SIZE_IN_KBYTES * 1024)>>9 ); // in 512 Byte Bloecke
disk->fops = &bdops;
add_disk( disk );
return 0;
out:
vfree( mempool );
out_no_mem:
unregister_blkdev(BD_MAJOR, "bdsample" );
return -EIO;
}
static void __exit mod_exit(void)
{
del_gendisk(disk);
put_disk( disk );
blk_cleanup_queue( bdqueue );
vfree( mempool );
unregister_blkdev(BD_MAJOR, "bdsample" );
}module_init( mod_init ); module_exit( mod_exit );
Then I wrote my own Program to call the ioctl:
int main(int argc, char *argv[]) {
int ret;
int file_desc; file_desc = open("/dev/bd0", 0);
ret = ioctl(file_desc, 3249, 0);
printf("result: %d\n", ret);
}/dev/bd0 is (242,0), what is the ramdisk. /proc/devices says after loading the module that bdsample is the driver for major 242. But calling the Programm results in the output:
result: -1
And in /var/log/messages no new entry of the ioctl is created. Only during insmod one entry "ioctl was called" was added. What is wrong with this?
If it is important: I use a i386-Architecture.
tschau
Sascha Effert fermat@xxxxxxxxxxxx Tel.:(0177) 6266652
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