From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id AEAE26B004D for ; Thu, 13 Aug 2009 15:58:12 -0400 (EDT) Date: Fri, 14 Aug 2009 04:57:39 +0900 From: Paul Mundt Subject: Re: question about nommu.c Message-ID: <20090813195738.GA8686@linux-sh.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Julia Lawall Cc: linux-mm@kvack.org List-ID: On Thu, Aug 13, 2009 at 09:41:38PM +0200, Julia Lawall wrote: > The function vmalloc_user in the file mm/nommu.c contains the following > code: > > struct vm_area_struct *vma; > ... > if (vma) > vma->vm_flags |= VM_USERMAP; > > The constant VM_USERMAP, however, is elsewhere used in a structure of type > vm_struct, not vm_area_struct. Furthermore, the value of VM_USERMAP is 8, > which is the same as the value of VM_SHARED (define in mm.h), which is > elsewhere used with a vm_area_struct structure. Is this occurrence of > VM_USERMAP correct? Or should it be VM_SHARED? Or should it be something > else? > Yes, this is currently broken, albeit generally harmless. I've been working on cleaning this up, but have not gotten around to posting patches yet. Part of this requires building on top of the infrastructure we have in place with the vm_regions to layer a proper vmap implementation on top of, which should in turn restore some meaning to the vmlist and permit struct vm_struct to be used on nommu properly. At the moment this is not a big problem as it doesn't really impact anything, it's more regarding future directions for the nommu memory management code. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org