Re: [PATCH] [8/7] oprofile - dcookies need to use u32

[David S. Miller]

   From: Ulrich Weigand <[e-mail]>
   Date: Wed, 16 Oct 2002 03:56:10 +0200 (MET DST)

   +               return (u32)dentry;
   
   Um, isn't this supposed to uniquely identify the dentry?
   On a platform with 64-bit pointers there's now the theoretical
   possibility of different dentries getting the same cookie ...

That's true.

We dealt with this (trying to use a kernel pointer as a cache held by
userspace) in tcp_diag by making the actual object opaque.  It was
actually two u32's, and that way it worked independant of kernel
vs. user word size.