copy_from_user returns a positive value?

From: Ben Greear (greearb@candelatech.com)
Date: Thu Feb 14 2002 - 21:10:20 EST

I have an IOCTL defined something like this:

        _IOWR (0xfe, (30<<3 + 0), __u8 [696])

I'm really passing in a structure of size 696 (does that matter)?

When I make the copy from user call:

       if ((ret = copy_from_user(&reqconf, arg, sizeof(reqconf)))) {
          printk("ERROR: copy_from_user returned: %i, sizeof(reqconf): %i\n",
                 ret, sizeof(reqconf));
          return ret;
       }

I see this printed out:

ERROR: copy_from_user returned: 696, sizeof(reqconf): 696

According to some docs I saw on the web, it should return 0, or the
number it has left to copy. So, why does it have 696 bytes left
to copy??

Thanks,
Ben 

-- 
Ben Greear <greearb@candelatech.com>       <Ben_Greear AT excite.com>
President of Candela Technologies Inc      http://www.candelatech.com
ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

This archive was generated by hypermail 2b29 : Fri Feb 15 2002 - 21:01:05 EST