On Tue, Mar 21, 2006 at 10:59:34PM +0530, pradeep singh wrote:
> this code is used to initialize the attribute .and creating the file.
>
> struct device_attribute * attr;
> if(i=device_register(dev))
> return i;
> attr=(struct device_attribute*)kmalloc(sizeof(struct
> device_attribute),GFP_KERNEL);
> if(NULL ==attr)
> {
> printk(KERN_ERR"Out of memory at %s",__FUNCTION__);
> device_unregister(dev);
> return FALSE;
> }
> memset(attr,0,sizeof(struct device_attribute));
> attr->attr.name="add_target";
> attr->attr.mode= S_IRUGO | S_IWUSR;
> attr->attr.owner=THIS_MODULE;
> attr->show=add_target_show;
> attr->store=add_target_store;
> to_vt_host_info(dev)->add_target=attr;
> device_create_file(dev ,to_vt_host_info(dev)->add_target);
> /* ... */
>
> the show function is :
>
> static ssize_t add_target_show(struct device * dev, char * buf)
> {
> struct vt_host_info *vthost=to_vt_host_info(dev);
>
> return(sprintf(buf, "%d\n", vthost->no_target));
>
> }
>
>
> When ever i cat the add_target file in/sys directory it doesnt
> displays anything.
> After this when i remove the module kernel panics:(.If i dont cat the
> add_target_file it doesnot gives me a panic on rmmod.
>
> Can anybody give me any pointers?
Use the proper DEV_ATTR() macro intead of trying to roll your own. And,
I bet you get a compiler warning when the code above compiles, do not
ignore it, it is pointing out your error...
thanks,
greg k-h
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