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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, virtualization@lists.osdl.org,
	xen-devel@lists.xensource.com,
	Ian Pratt <ian.pratt@xensource.com>,
	Christian Limpach <Christian.Limpach@cl.cam.ac.uk>,
	Chris Wright <chrisw@sous-sol.org>,
	Christoph Lameter <clameter@sgi.com>
Subject: [patch 11/20] XEN-paravirt: Add apply_to_page_range() which applies a function to a pte range.
Date: Fri, 12 Jan 2007 17:45:50 -0800	[thread overview]
Message-ID: <20070113014648.210731977@goop.org> (raw)
In-Reply-To: <20070113014539.408244126@goop.org>

[-- Attachment #1: apply-to-page-range.patch --]
[-- Type: text/plain, Size: 4118 bytes --]

Add a new mm function apply_to_page_range() which applies a given
function to every pte in a given virtual address range in a given mm
structure. This is a generic alternative to cut-and-pasting the Linux
idiomatic pagetable walking code in every place that a sequence of
PTEs must be accessed.

Although this interface is intended to be useful in a wide range of
situations, it is currently used specifically by several Xen
subsystems, for example: to ensure that pagetables have been allocated
for a virtual address range, and to construct batched special
pagetable update requests to map I/O memory (in ioremap()).

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Christoph Lameter <clameter@sgi.com>

---
 include/linux/mm.h |    5 ++
 mm/memory.c        |   94 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)

===================================================================
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1130,6 +1130,11 @@ struct page *follow_page(struct vm_area_
 
 unsigned long __follow_page(void *vaddr);
 
+typedef int (*pte_fn_t)(pte_t *pte, struct page *pmd_page, unsigned long addr,
+			void *data);
+extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
+			       unsigned long size, pte_fn_t fn, void *data);
+
 #ifdef CONFIG_PROC_FS
 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
 #else
===================================================================
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1414,6 +1414,100 @@ int remap_pfn_range(struct vm_area_struc
 }
 EXPORT_SYMBOL(remap_pfn_range);
 
+static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
+				     unsigned long addr, unsigned long end,
+				     pte_fn_t fn, void *data)
+{
+	pte_t *pte;
+	int err;
+	struct page *pmd_page;
+	spinlock_t *ptl;
+
+	pte = (mm == &init_mm) ?
+		pte_alloc_kernel(pmd, addr) :
+		pte_alloc_map_lock(mm, pmd, addr, &ptl);
+	if (!pte)
+		return -ENOMEM;
+
+	BUG_ON(pmd_huge(*pmd));
+
+	pmd_page = pmd_page(*pmd);
+
+	do {
+		err = fn(pte, pmd_page, addr, data);
+		if (err)
+			break;
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+
+	if (mm != &init_mm)
+		pte_unmap_unlock(pte-1, ptl);
+	return err;
+}
+
+static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
+				     unsigned long addr, unsigned long end,
+				     pte_fn_t fn, void *data)
+{
+	pmd_t *pmd;
+	unsigned long next;
+	int err;
+
+	pmd = pmd_alloc(mm, pud, addr);
+	if (!pmd)
+		return -ENOMEM;
+	do {
+		next = pmd_addr_end(addr, end);
+		err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
+		if (err)
+			break;
+	} while (pmd++, addr = next, addr != end);
+	return err;
+}
+
+static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
+				     unsigned long addr, unsigned long end,
+				     pte_fn_t fn, void *data)
+{
+	pud_t *pud;
+	unsigned long next;
+	int err;
+
+	pud = pud_alloc(mm, pgd, addr);
+	if (!pud)
+		return -ENOMEM;
+	do {
+		next = pud_addr_end(addr, end);
+		err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
+		if (err)
+			break;
+	} while (pud++, addr = next, addr != end);
+	return err;
+}
+
+/*
+ * Scan a region of virtual memory, filling in page tables as necessary
+ * and calling a provided function on each leaf page table.
+ */
+int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
+			unsigned long size, pte_fn_t fn, void *data)
+{
+	pgd_t *pgd;
+	unsigned long next;
+	unsigned long end = addr + size;
+	int err;
+
+	BUG_ON(addr >= end);
+	pgd = pgd_offset(mm, addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
+		if (err)
+			break;
+	} while (pgd++, addr = next, addr != end);
+	return err;
+}
+EXPORT_SYMBOL_GPL(apply_to_page_range);
+
 /*
  * handle_pte_fault chooses page fault handler according to an entry
  * which was read non-atomically.  Before making any commitment, on

-- 


  parent reply	other threads:[~2007-01-13 23:11 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-13  1:45 [patch 00/20] XEN-paravirt: Xen guest implementation for paravirt_ops interface Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 01/20] XEN-paravirt: Fix typo in sync_constant_test_bit()s name Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 02/20] XEN-paravirt: Add a flag to allow the VGA console to be disabled Jeremy Fitzhardinge
2007-01-14  0:27   ` [Xen-devel] " Alan
2007-01-13  1:45 ` [patch 03/20] XEN-paravirt: paravirt: page-table accessors Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 04/20] XEN-paravirt: paravirt pagetable init Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 05/20] XEN-paravirt: paravirt: reserve fixmap slot Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 06/20] XEN-paravirt: remove pgd ctor Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 07/20] XEN-paravirt: paravirt shared kernel pmd flag Jeremy Fitzhardinge
2007-01-15  8:59   ` [Xen-devel] " Jan Beulich
2007-01-13  1:45 ` [patch 08/20] XEN-paravirt: paravirt pgd allocation alignment Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 09/20] XEN-paravirt: dont export paravirt_ops structure, do individual functions Jeremy Fitzhardinge
2007-01-14  0:57   ` Rusty Russell
2007-01-13  1:45 ` [patch 10/20] XEN-paravirt: mm lifetime hooks Jeremy Fitzhardinge
2007-01-13  1:45 ` Jeremy Fitzhardinge [this message]
2007-01-13  1:45 ` [patch 12/20] XEN-paravirt: Xen: Add nosegneg capability to the vsyscall page notes Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 13/20] XEN-paravirt: Xen: Add config options and disable unsupported config options Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 15/20] XEN-paravirt: Xen: core paravirt guest changes Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 16/20] XEN-paravirt: Add the Xen virtual console driver Jeremy Fitzhardinge
2007-01-14  0:37   ` Alan
2007-01-14  0:35     ` Jeremy Fitzhardinge
2007-01-15 13:03   ` Pavel Machek
2007-01-19  4:11     ` Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 17/20] XEN-paravirt: Add Xen grant table support Jeremy Fitzhardinge
2007-01-15 13:05   ` Pavel Machek
2007-01-19  4:07     ` Jeremy Fitzhardinge
2007-01-13  1:45 ` [patch 18/20] XEN-paravirt: Add Xen driver utility functions Jeremy Fitzhardinge
2007-01-14  7:41   ` Greg KH
2007-01-13  1:45 ` [patch 19/20] XEN-paravirt: Add the Xenbus sysfs and virtual device hotplug driver Jeremy Fitzhardinge
2007-01-15 13:18   ` Pavel Machek
2007-01-13  1:45 ` [patch 20/20] XEN-paravirt: Add Xen virtual block device driver Jeremy Fitzhardinge
2007-01-14  1:07   ` Arjan van de Ven
2007-01-14  7:43     ` Greg KH
2007-01-16  2:53     ` [Xen-devel] " Mark Williamson
2007-01-14 11:05   ` Jan Engelhardt
2007-01-14 11:24     ` Muli Ben-Yehuda
2007-01-14 11:35       ` Jan Engelhardt
2007-01-14 12:37     ` Keir Fraser

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