Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756529AbYGGR7P (ORCPT ); Mon, 7 Jul 2008 13:59:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753910AbYGGR7A (ORCPT ); Mon, 7 Jul 2008 13:59:00 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:43643 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754113AbYGGR67 (ORCPT ); Mon, 7 Jul 2008 13:58:59 -0400 Date: Mon, 7 Jul 2008 12:58:58 -0500 From: Jack Steiner To: Christoph Hellwig , cl@linux-foundation.org, hugh@veritas.com Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, holt@sgi.com, andrea@qumranet.com, linux-mm@kvack.org Subject: Re: [patch 12/13] GRU Driver V3 - export is_uv_system(), zap_page_range() & follow_page() Message-ID: <20080707175858.GA1927@sgi.com> References: <20080703213348.489120321@attica.americas.sgi.com> <20080703213633.890647632@attica.americas.sgi.com> <20080704073926.GA1449@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080704073926.GA1449@infradead.org> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2831 Lines: 86 On Fri, Jul 04, 2008 at 03:39:26AM -0400, Christoph Hellwig wrote: > On Thu, Jul 03, 2008 at 04:34:00PM -0500, steiner@sgi.com wrote: > > +EXPORT_SYMBOL_GPL(zap_page_range); > > > > NACK. > I agree that zap_pages_range() is more general than what is needed. How about the following. This should prevent abuse of the API & provide what (I think) drivers need. Verified with GRU & XPMEM. --- jack -------------------------------------------------------------------------------------------- Add function to unmap driver ptes. zap_vma_ptes() is intended to be used by drivers to unmap ptes assigned to the driver private vmas. This interface is similar to zap_page_range() but is less general & less likely to be abused. Signed-off-by: Jack Steiner --- include/linux/mm.h | 2 ++ mm/memory.c | 23 +++++++++++++++++++++++ 2 files changed, 25 insertions(+) Index: linux/include/linux/mm.h =================================================================== --- linux.orig/include/linux/mm.h 2008-07-07 12:22:17.809892803 -0500 +++ linux/include/linux/mm.h 2008-07-07 12:22:56.126695482 -0500 @@ -742,6 +742,8 @@ struct zap_details { struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte); +int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, + unsigned long size); unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size, struct zap_details *); unsigned long unmap_vmas(struct mmu_gather **tlb, Index: linux/mm/memory.c =================================================================== --- linux.orig/mm/memory.c 2008-07-07 12:22:18.357961503 -0500 +++ linux/mm/memory.c 2008-07-07 12:31:51.097688882 -0500 @@ -978,6 +978,29 @@ unsigned long zap_page_range(struct vm_a } EXPORT_SYMBOL_GPL(zap_page_range); +/** + * zap_vma_ptes - remove ptes mapping the vma + * @vma: vm_area_struct holding ptes to be zapped + * @address: starting address of pages to zap + * @size: number of bytes to zap + * + * This function only unmaps ptes assigned to VM_PFNMAP vmas. + * + * The entire address range must be fully contained within the vma. + * + * Returns 0 if successful. + */ +int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, + unsigned long size) +{ + if (address < vma->vm_start || address + size > vma->vm_end || + !(vma->vm_flags & VM_PFNMAP)) + return -1; + zap_page_range(vma, address, size, NULL); + return 0; +} +EXPORT_SYMBOL_GPL(zap_vma_ptes); + /* * Do a quick page-table lookup for a single page. */ -- 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/