From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765968AbXJPE6x (ORCPT ); Tue, 16 Oct 2007 00:58:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765815AbXJPE6m (ORCPT ); Tue, 16 Oct 2007 00:58:42 -0400 Received: from smtp-out.google.com ([216.239.45.13]:50628 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765493AbXJPE6k (ORCPT ); Tue, 16 Oct 2007 00:58:40 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:date:from:x-x-sender:to:cc:subject:in-reply-to: message-id:references:mime-version:content-type; b=D763J9KHGwCO6ZVA8lgxFFAqvuLBYd5ystHd9XHUca3yWl3SP8wSEcyU27CtAdTFW G9DH7Yn+NR0MuIBuAk9gg== Date: Mon, 15 Oct 2007 21:58:11 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Matt Mackall cc: Andrew Morton , linux-kernel@vger.kernel.org, Dave Hansen , Rusty Russell , Jeremy Fitzhardinge , Fengguang Wu Subject: Re: [PATCH 4/11] maps3: introduce a generic page walker In-Reply-To: <5.290135367@selenic.com> Message-ID: References: <5.290135367@selenic.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Oct 2007, Matt Mackall wrote: > Introduce a general page table walker > > Signed-off-by: Matt Mackall > > Index: l/include/linux/mm.h > =================================================================== > --- l.orig/include/linux/mm.h 2007-10-09 17:37:59.000000000 -0500 > +++ l/include/linux/mm.h 2007-10-10 11:46:37.000000000 -0500 > @@ -773,6 +773,17 @@ unsigned long unmap_vmas(struct mmu_gath > struct vm_area_struct *start_vma, unsigned long start_addr, > unsigned long end_addr, unsigned long *nr_accounted, > struct zap_details *); > + > +struct mm_walk { > + int (*pgd_entry)(pgd_t *, unsigned long, unsigned long, void *); > + int (*pud_entry)(pud_t *, unsigned long, unsigned long, void *); > + int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, void *); > + int (*pte_entry)(pte_t *, unsigned long, unsigned long, void *); > + int (*pte_hole) (unsigned long, unsigned long, void *); > +}; > + > +int walk_page_range(struct mm_struct *, unsigned long addr, unsigned long end, > + struct mm_walk *walk, void *private); The struct mm_walk * can be qualified as const. > Index: l/mm/pagewalk.c > =================================================================== > --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ l/mm/pagewalk.c 2007-10-10 11:46:37.000000000 -0500 > @@ -0,0 +1,120 @@ > +#include > +#include > +#include > + > +static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, > + struct mm_walk *walk, void *private) > +{ > + pte_t *pte; > + int err = 0; > + > + pte = pte_offset_map(pmd, addr); > + do { > + err = walk->pte_entry(pte, addr, addr, private); > + if (err) > + break; > + } while (pte++, addr += PAGE_SIZE, addr != end); > + > + pte_unmap(pte); > + return err; > +} > + > +static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, > + struct mm_walk *walk, void *private) > +{ > + pmd_t *pmd; > + unsigned long next; > + int err = 0; > + > + pmd = pmd_offset(pud, addr); > + do { > + next = pmd_addr_end(addr, end); > + if (pmd_none_or_clear_bad(pmd)) { > + if (walk->pte_hole) > + err = walk->pte_hole(addr, next, private); > + if (err) > + break; > + continue; > + } > + if (walk->pmd_entry) > + err = walk->pmd_entry(pmd, addr, next, private); > + if (!err && walk->pte_entry) > + err = walk_pte_range(pmd, addr, next, walk, private); > + if (err) > + break; > + } while (pmd++, addr = next, addr != end); > + > + return err; > +} > + > +static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, > + struct mm_walk *walk, void *private) > +{ > + pud_t *pud; > + unsigned long next; > + int err = 0; > + > + pud = pud_offset(pgd, addr); > + do { > + next = pud_addr_end(addr, end); > + if (pud_none_or_clear_bad(pud)) { > + if (walk->pte_hole) > + err = walk->pte_hole(addr, next, private); > + if (err) > + break; > + continue; > + } > + if (walk->pud_entry) > + err = walk->pud_entry(pud, addr, next, private); > + if (!err && (walk->pmd_entry || walk->pte_entry)) > + err = walk_pmd_range(pud, addr, next, walk, private); > + if (err) > + break; > + } while (pud++, addr = next, addr != end); > + > + return err; > +} > + > +/* > + * walk_page_range - walk a memory map's page tables with a callback > + * @mm - memory map to walk > + * @addr - starting address > + * @end - ending address > + * @walk - set of callbacks to invoke for each level of the tree > + * @private - private data passed to the callback function > + * > + * Recursively walk the page table for the memory area in a VMA, calling > + * a callback for every bottom-level (PTE) page table. > + */ > +int walk_page_range(struct mm_struct *mm, > + unsigned long addr, unsigned long end, > + struct mm_walk *walk, void *private) > +{ > + pgd_t *pgd; > + unsigned long next; > + int err = 0; > + > + if (addr >= end) > + return err; unlikely? > + > + pgd = pgd_offset(mm, addr); > + do { > + next = pgd_addr_end(addr, end); > + if (pgd_none_or_clear_bad(pgd)) { > + if (walk->pte_hole) > + err = walk->pte_hole(addr, next, private); > + if (err) > + break; > + continue; > + } > + if (walk->pgd_entry) > + err = walk->pgd_entry(pgd, addr, next, private); > + if (!err && > + (walk->pud_entry || walk->pmd_entry || walk->pte_entry)) > + err = walk_pud_range(pgd, addr, next, walk, private); > + if (err) > + return err; break instead. > + } while (pgd++, addr = next, addr != end); > + > + return err; > +} Should walk_page_range be exported? Is it trivial to convert ioremap to use this new pte walker?