driver copy_to_user

Mulyadi Santosa mulyadi.santosa at
Fri Dec 24 13:29:43 EST 2010


On Fri, Dec 24, 2010 at 13:40, Hemanth Kumar <hemwire at> wrote:
> Hi mulyadi,
>          Sorry for sending the mail directly,

It's ok, but just to let you know..I am just average when dealing with kernel :)

> ssize_t my_read(struct file *file,char *buf,size_t count,loff_t *pos){
>     unsigned long res;
>     void *k = (void *)&x;
>          void *l = (void *)&x+1;
>          void *j = (void *)&x+2;
>                     mutex_lock(&timer);
>                             res =    copy_to_user(buf,k,sizeof(short));

hm, you say "read from user space", right? Then why "copy_to_user"?
shouldn't it be "copy_from_user"?

Mulyadi Santosa
Freelance Linux trainer and consultant


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