copy_from_user returns a positive value?

[Ben Greear <greearb@candelatech.com>]

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
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