Re: [RFC][PATCH] Convert do_no_page() to a hook to avoid DFS race

["Paul E. McKenney" <paulmck@us.ibm.com>]

On Fri, May 30, 2003 at 06:00:27PM -0700, Andrew Morton wrote:
> "Paul E. McKenney" <paulmck@us.ibm.com> wrote:
> > An alternative to this patch includes the nopagedone() patch posted
> > moments ago.  hch has also suggested that do_anonymous_page() be
> > converted to a ->nopage callout, but this would require that all
> > of the other ->nopage callouts drop mm->page_table_lock as their
> > first action.  If people believe that this is the right thing to
> > do, I will happily produce such a patch.
> 
> That sounds better to me.

Here is a patch, compiled on i386, untested.  I had to put the
pte_unmap() as well as the spin_unlock() into each ->nopage
function.  I would guess that this might be more attractive
if combined with a fix for the pagefault-truncate() race.  ;-)

					Thanx, Paul

diff -urN -X dontdiff linux-2.5.70-mm3/arch/i386/mm/hugetlbpage.c linux-2.5.70-mm3.install_new_page_hch/arch/i386/mm/hugetlbpage.c
--- linux-2.5.70-mm3/arch/i386/mm/hugetlbpage.c	2003-05-26 18:00:58.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/arch/i386/mm/hugetlbpage.c	2003-06-01 10:43:06.000000000 -0700
@@ -487,11 +487,13 @@
  * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
  * this far.
  */
-static struct page *hugetlb_nopage(struct vm_area_struct *vma,
-				unsigned long address, int unused)
+static int hugetlb_nopage(struct mm_struct *mm, struct vm_area_struct *vma,
+			  unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 {
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	BUG();
-	return NULL;
+	return VM_FAULT_SIGBUS;
 }
 
 struct vm_operations_struct hugetlb_vm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/arch/ia64/ia32/binfmt_elf32.c linux-2.5.70-mm3.install_new_page_hch/arch/ia64/ia32/binfmt_elf32.c
--- linux-2.5.70-mm3/arch/ia64/ia32/binfmt_elf32.c	2003-05-26 18:00:58.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/arch/ia64/ia32/binfmt_elf32.c	2003-06-01 10:43:27.000000000 -0700
@@ -56,13 +56,15 @@
 extern struct page *ia32_shared_page[];
 extern unsigned long *ia32_gdt;
 
-struct page *
-ia32_install_shared_page (struct vm_area_struct *vma, unsigned long address, int no_share)
+int
+ia32_install_shared_page (struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	struct page *pg = ia32_shared_page[(address - vma->vm_start)/PAGE_SIZE];
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	get_page(pg);
-	return pg;
+	return install_new_page(mm, vma, address, write_access, pmd, pg);
 }
 
 static struct vm_operations_struct ia32_shared_page_vm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/arch/ia64/kernel/perfmon.c linux-2.5.70-mm3.install_new_page_hch/arch/ia64/kernel/perfmon.c
--- linux-2.5.70-mm3/arch/ia64/kernel/perfmon.c	2003-05-26 18:00:58.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/arch/ia64/kernel/perfmon.c	2003-06-01 10:12:48.000000000 -0700
@@ -424,7 +424,8 @@
 static void pfm_vm_close(struct vm_area_struct * area);
 
 static struct vm_operations_struct pfm_vm_ops={
-	.close = pfm_vm_close
+	.close = pfm_vm_close,
+	.nopage = do_anonymous_page
 };
 
 /*
diff -urN -X dontdiff linux-2.5.70-mm3/arch/ia64/mm/hugetlbpage.c linux-2.5.70-mm3.install_new_page_hch/arch/ia64/mm/hugetlbpage.c
--- linux-2.5.70-mm3/arch/ia64/mm/hugetlbpage.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/arch/ia64/mm/hugetlbpage.c	2003-06-01 10:44:02.000000000 -0700
@@ -479,10 +479,12 @@
 	return 1;
 }
 
-static struct page *hugetlb_nopage(struct vm_area_struct * area, unsigned long address, int unused)
+static int hugetlb_nopage(struct mm_struct * mm, struct vm_area_struct * area, unsigned long address, int write_access, pte_t * page_table, pmd_t * pmd)
 {
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	BUG();
-	return NULL;
+	return VM_FAULT_SIGBUS;
 }
 
 struct vm_operations_struct hugetlb_vm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/arch/sparc64/mm/hugetlbpage.c linux-2.5.70-mm3.install_new_page_hch/arch/sparc64/mm/hugetlbpage.c
--- linux-2.5.70-mm3/arch/sparc64/mm/hugetlbpage.c	2003-05-26 18:00:42.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/arch/sparc64/mm/hugetlbpage.c	2003-06-01 10:44:21.000000000 -0700
@@ -633,11 +633,13 @@
 	return (int) htlbzone_pages;
 }
 
-static struct page *
-hugetlb_nopage(struct vm_area_struct *vma, unsigned long address, int unused)
+static int
+hugetlb_nopage(struct mm_struct * mm, struct vm_area_struct *vma, unsigned long address, int write_access, pte_t *page_table, pmd_t * pmd)
 {
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	BUG();
-	return NULL;
+	return VM_FAULT_SIGBUS;
 }
 
 static struct vm_operations_struct hugetlb_vm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/char/agp/alpha-agp.c linux-2.5.70-mm3.install_new_page_hch/drivers/char/agp/alpha-agp.c
--- linux-2.5.70-mm3/drivers/char/agp/alpha-agp.c	2003-05-26 18:00:42.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/char/agp/alpha-agp.c	2003-06-01 10:44:53.000000000 -0700
@@ -11,26 +11,28 @@
 
 #include "agp.h"
 
-static struct page *alpha_core_agp_vm_nopage(struct vm_area_struct *vma,
-					     unsigned long address,
-					     int write_access)
+static int alpha_core_agp_vm_nopage(struct mm_struct *mm, struct vm_area_struct *vma,
+				    unsigned long address,
+				    int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	alpha_agp_info *agp = agp_bridge->dev_private_data;
 	dma_addr_t dma_addr;
 	unsigned long pa;
 	struct page *page;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	dma_addr = address - vma->vm_start + agp->aperture.bus_base;
 	pa = agp->ops->translate(agp, dma_addr);
 
-	if (pa == (unsigned long)-EINVAL) return NULL;	/* no translation */
+	if (pa == (unsigned long)-EINVAL) return VM_FAULT_SIGBUS; /* no translation */
 	
 	/*
 	 * Get the page, inc the use count, and return it
 	 */
 	page = virt_to_page(__va(pa));
 	get_page(page);
-	return page;
+	return install_new_page(mm, vma, address, write_access, pmd, page);
 }
 
 static struct aper_size_info_fixed alpha_core_agp_sizes[] =
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/char/drm/drmP.h linux-2.5.70-mm3.install_new_page_hch/drivers/char/drm/drmP.h
--- linux-2.5.70-mm3/drivers/char/drm/drmP.h	2003-05-26 18:00:45.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/char/drm/drmP.h	2003-06-01 11:16:09.000000000 -0700
@@ -620,18 +620,17 @@
 extern int	     DRM(fasync)(int fd, struct file *filp, int on);
 
 				/* Mapping support (drm_vm.h) */
-extern struct page *DRM(vm_nopage)(struct vm_area_struct *vma,
-				   unsigned long address,
-				   int write_access);
-extern struct page *DRM(vm_shm_nopage)(struct vm_area_struct *vma,
-				       unsigned long address,
-				       int write_access);
-extern struct page *DRM(vm_dma_nopage)(struct vm_area_struct *vma,
-				       unsigned long address,
-				       int write_access);
-extern struct page *DRM(vm_sg_nopage)(struct vm_area_struct *vma,
-				      unsigned long address,
-				      int write_access);
+extern int DRM(vm_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			  unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd);
+extern int DRM(vm_shm_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			      unsigned long address,
+			      int write_access, pte_t *page_table, pmd_t *pmd);
+extern int DRM(vm_dma_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			      unsigned long address,
+			      int write_access, pte_t *page_table, pmd_t *pmd);
+extern int DRM(vm_sg_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			     unsigned long address,
+			     int write_access, pte_t *page_table, pmd_t *pmd);
 extern void	     DRM(vm_open)(struct vm_area_struct *vma);
 extern void	     DRM(vm_close)(struct vm_area_struct *vma);
 extern void	     DRM(vm_shm_close)(struct vm_area_struct *vma);
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/char/drm/drm_vm.h linux-2.5.70-mm3.install_new_page_hch/drivers/char/drm/drm_vm.h
--- linux-2.5.70-mm3/drivers/char/drm/drm_vm.h	2003-05-26 18:01:02.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/char/drm/drm_vm.h	2003-06-01 10:28:54.000000000 -0700
@@ -55,10 +55,12 @@
 	.close  = DRM(vm_close),
 };
 
-struct page *DRM(vm_nopage)(struct vm_area_struct *vma,
-			    unsigned long address,
-			    int write_access)
+int DRM(vm_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+		   unsigned long address,
+		   int write_access, pte_t *page_table, pmd_t *pmd)
 {
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 #if __REALLY_HAVE_AGP
 	drm_file_t *priv  = vma->vm_file->private_data;
 	drm_device_t *dev = priv->dev;
@@ -114,35 +116,37 @@
 			  baddr, __va(agpmem->memory->memory[offset]), offset,
 			  atomic_read(&page->count));
 
-		return page;
+		return install_new_page(mm, vma, address, write_access, pmd, page);
         }
 vm_nopage_error:
 #endif /* __REALLY_HAVE_AGP */
 
-	return NOPAGE_SIGBUS;		/* Disallow mremap */
+	return VM_FAULT_SIGBUS;		/* Disallow mremap */
 }
 
-struct page *DRM(vm_shm_nopage)(struct vm_area_struct *vma,
-				unsigned long address,
-				int write_access)
+int DRM(vm_shm_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+		       unsigned long address,
+		       int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	drm_map_t	 *map	 = (drm_map_t *)vma->vm_private_data;
 	unsigned long	 offset;
 	unsigned long	 i;
 	struct page	 *page;
 
-	if (address > vma->vm_end) return NOPAGE_SIGBUS; /* Disallow mremap */
-	if (!map)    		   return NOPAGE_OOM;  /* Nothing allocated */
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
+	if (address > vma->vm_end) return VM_FAULT_SIGBUS; /* Disallow mremap */
+	if (!map)    		   return VM_FAULT_OOM;  /* Nothing allocated */
 
 	offset	 = address - vma->vm_start;
 	i = (unsigned long)map->handle + offset;
 	page = vmalloc_to_page((void *)i);
 	if (!page)
-		return NOPAGE_OOM;
+		return VM_FAULT_OOM;
 	get_page(page);
 
 	DRM_DEBUG("shm_nopage 0x%lx\n", address);
-	return page;
+	return install_new_page(mm, vma, address, write_access, pmd, page);
 }
 
 /* Special close routine which deletes map information if we are the last
@@ -221,9 +225,9 @@
 	up(&dev->struct_sem);
 }
 
-struct page *DRM(vm_dma_nopage)(struct vm_area_struct *vma,
-				unsigned long address,
-				int write_access)
+int DRM(vm_dma_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+		       unsigned long address,
+		       int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	drm_file_t	 *priv	 = vma->vm_file->private_data;
 	drm_device_t	 *dev	 = priv->dev;
@@ -232,9 +236,11 @@
 	unsigned long	 page_nr;
 	struct page	 *page;
 
-	if (!dma)		   return NOPAGE_SIGBUS; /* Error */
-	if (address > vma->vm_end) return NOPAGE_SIGBUS; /* Disallow mremap */
-	if (!dma->pagelist)	   return NOPAGE_OOM ; /* Nothing allocated */
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
+	if (!dma)		   return VM_FAULT_SIGBUS; /* Error */
+	if (address > vma->vm_end) return VM_FAULT_SIGBUS; /* Disallow mremap */
+	if (!dma->pagelist)	   return VM_FAULT_OOM ; /* Nothing allocated */
 
 	offset	 = address - vma->vm_start; /* vm_[pg]off[set] should be 0 */
 	page_nr  = offset >> PAGE_SHIFT;
@@ -244,12 +250,12 @@
 	get_page(page);
 
 	DRM_DEBUG("dma_nopage 0x%lx (page %lu)\n", address, page_nr);
-	return page;
+	return install_new_page(mm, vma, address, write_access, pmd, page);
 }
 
-struct page *DRM(vm_sg_nopage)(struct vm_area_struct *vma,
-			       unsigned long address,
-			       int write_access)
+int DRM(vm_sg_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+		      unsigned long address,
+		      int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	drm_map_t        *map    = (drm_map_t *)vma->vm_private_data;
 	drm_file_t *priv = vma->vm_file->private_data;
@@ -260,9 +266,11 @@
 	unsigned long page_offset;
 	struct page *page;
 
-	if (!entry)                return NOPAGE_SIGBUS; /* Error */
-	if (address > vma->vm_end) return NOPAGE_SIGBUS; /* Disallow mremap */
-	if (!entry->pagelist)      return NOPAGE_OOM ;  /* Nothing allocated */
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
+	if (!entry)                return VM_FAULT_SIGBUS; /* Error */
+	if (address > vma->vm_end) return VM_FAULT_SIGBUS; /* Disallow mremap */
+	if (!entry->pagelist)      return VM_FAULT_OOM ; /* Nothing allocated */
 
 
 	offset = address - vma->vm_start;
@@ -271,7 +279,7 @@
 	page = entry->pagelist[page_offset];
 	get_page(page);
 
-	return page;
+	return install_new_page(mm, vma, address, write_access, pmd, page);
 }
 
 void DRM(vm_open)(struct vm_area_struct *vma)
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/char/ftape/zftape/zftape-init.c linux-2.5.70-mm3.install_new_page_hch/drivers/char/ftape/zftape/zftape-init.c
--- linux-2.5.70-mm3/drivers/char/ftape/zftape/zftape-init.c	2003-05-26 18:00:38.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/char/ftape/zftape/zftape-init.c	2003-06-01 10:15:32.000000000 -0700
@@ -198,7 +198,7 @@
 	sigfillset(&current->blocked);
 	if ((result = ftape_mmap(vma)) >= 0) {
 #ifndef MSYNC_BUG_WAS_FIXED
-		static struct vm_operations_struct dummy = { NULL, };
+		static struct vm_operations_struct dummy = { .nopage = do_anonymous_page, };
 		vma->vm_ops = &dummy;
 #endif
 	}
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/ieee1394/dma.c linux-2.5.70-mm3.install_new_page_hch/drivers/ieee1394/dma.c
--- linux-2.5.70-mm3/drivers/ieee1394/dma.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/ieee1394/dma.c	2003-06-01 10:29:36.000000000 -0700
@@ -184,28 +184,29 @@
 
 /* nopage() handler for mmap access */
 
-static struct page*
-dma_region_pagefault(struct vm_area_struct *area, unsigned long address, int write_access)
+static int
+dma_region_pagefault(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	unsigned long offset;
 	unsigned long kernel_virt_addr;
-	struct page *ret = NOPAGE_SIGBUS;
+	struct page *page;
 
 	struct dma_region *dma = (struct dma_region*) area->vm_private_data;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	if(!dma->kvirt)
-		goto out;
+		return VM_FAULT_SIGBUS;
 
 	if( (address < (unsigned long) area->vm_start) ||
 	    (address > (unsigned long) area->vm_start + (PAGE_SIZE * dma->n_pages)) )
-		goto out;
+		return VM_FAULT_SIGBUS;
 
 	offset = address - area->vm_start;
 	kernel_virt_addr = (unsigned long) dma->kvirt + offset;
-	ret = vmalloc_to_page((void*) kernel_virt_addr);
-	get_page(ret);
-out:
-	return ret;
+	page = vmalloc_to_page((void*) kernel_virt_addr);
+	get_page(page);
+	return install_new_page(mm, vma, address, write_access, pmd, page);
 }
 
 static struct vm_operations_struct dma_region_vm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/media/video/video-buf.c linux-2.5.70-mm3.install_new_page_hch/drivers/media/video/video-buf.c
--- linux-2.5.70-mm3/drivers/media/video/video-buf.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/media/video/video-buf.c	2003-06-01 10:30:39.000000000 -0700
@@ -979,21 +979,23 @@
  * now ...).  Bounce buffers don't work very well for the data rates
  * video capture has.
  */
-static struct page*
-videobuf_vm_nopage(struct vm_area_struct *vma, unsigned long vaddr,
-		  int write_access)
+static int
+videobuf_vm_nopage(struct mm_struct *mm, struct vm_area_struct *vma,
+		   unsigned long vaddr, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	struct page *page;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	dprintk(3,"nopage: fault @ %08lx [vma %08lx-%08lx]\n",
 		vaddr,vma->vm_start,vma->vm_end);
         if (vaddr > vma->vm_end)
-		return NOPAGE_SIGBUS;
+		return VM_FAULT_SIGBUS;
 	page = alloc_page(GFP_USER);
 	if (!page)
-		return NOPAGE_OOM;
+		return VM_FAULT_OOM;
 	clear_user_page(page_address(page), vaddr, page);
-	return page;
+	return install_new_page(mm, vma, vaddr, write_access, pmd, page);
 }
 
 static struct vm_operations_struct videobuf_vm_ops =
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/scsi/sg.c linux-2.5.70-mm3.install_new_page_hch/drivers/scsi/sg.c
--- linux-2.5.70-mm3/drivers/scsi/sg.c	2003-05-31 16:31:06.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/scsi/sg.c	2003-06-01 10:31:24.000000000 -0700
@@ -1121,21 +1121,23 @@
 	}
 }
 
-static struct page *
-sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int unused)
+static int
+sg_vma_nopage(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	Sg_fd *sfp;
-	struct page *page = NOPAGE_SIGBUS;
+	struct page *page = VM_FAULT_SIGBUS;
 	void *page_ptr = NULL;
 	unsigned long offset;
 	Sg_scatter_hold *rsv_schp;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
-		return page;
+		return install_new_page(mm, vma, addr, write_access, pmd, page);
 	rsv_schp = &sfp->reserve;
 	offset = addr - vma->vm_start;
 	if (offset >= rsv_schp->bufflen)
-		return page;
+		return install_new_page(mm, vma, addr, write_access, pmd, page);
 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_nopage: offset=%lu, scatg=%d\n",
 				   offset, rsv_schp->k_use_sg));
 	if (rsv_schp->k_use_sg) {	/* reserve buffer is a scatter gather list */
@@ -1162,7 +1164,7 @@
 		page = virt_to_page(page_ptr);
 		get_page(page);	/* increment page count */
 	}
-	return page;
+	return install_new_page(mm, vma, addr, write_access, pmd, page);
 }
 
 static struct vm_operations_struct sg_mmap_vm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/sgi/char/graphics.c linux-2.5.70-mm3.install_new_page_hch/drivers/sgi/char/graphics.c
--- linux-2.5.70-mm3/drivers/sgi/char/graphics.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/sgi/char/graphics.c	2003-06-01 10:32:03.000000000 -0700
@@ -211,9 +211,9 @@
 /* 
  * This is the core of the direct rendering engine.
  */
-struct page *
-sgi_graphics_nopage (struct vm_area_struct *vma, unsigned long address, int
-		     no_share)
+struct int
+sgi_graphics_nopage (struct mm_struct *mm, struct vm_area_struct *vma,
+		     unsigned long address, int write_access, pte_t *page_table, pmd_t *pmdpf)
 {
 	pgd_t *pgd; pmd_t *pmd; pte_t *pte; 
 	int board = GRAPHICS_CARD (vma->vm_dentry->d_inode->i_rdev);
@@ -221,6 +221,8 @@
 	unsigned long virt_add, phys_add;
 	struct page * page;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 #ifdef DEBUG
 	printk ("Got a page fault for board %d address=%lx guser=%lx\n", board,
 		address, (unsigned long) cards[board].g_user);
@@ -249,7 +251,7 @@
 	pte = pte_kmap_offset(pmd, address);
 	page = pte_page(*pte);
 	pte_kunmap(pte);
-	return page;
+	return install_new_page(mm, vma, address, write_access, pmdpf, page);
 }
 
 /*
diff -urN -X dontdiff linux-2.5.70-mm3/drivers/sgi/char/shmiq.c linux-2.5.70-mm3.install_new_page_hch/drivers/sgi/char/shmiq.c
--- linux-2.5.70-mm3/drivers/sgi/char/shmiq.c	2003-05-26 18:00:45.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/drivers/sgi/char/shmiq.c	2003-06-01 10:33:13.000000000 -0700
@@ -303,11 +303,11 @@
 }
 
 struct page *
-shmiq_nopage (struct vm_area_struct *vma, unsigned long address,
-              int write_access)
+shmiq_nopage (struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address,
+              int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	/* Do not allow for mremap to expand us */
-	return NULL;
+	return VM_FAULT_SIGBUS;
 }
 
 static struct vm_operations_struct qcntl_mmap = {
diff -urN -X dontdiff linux-2.5.70-mm3/fs/ncpfs/mmap.c linux-2.5.70-mm3.install_new_page_hch/fs/ncpfs/mmap.c
--- linux-2.5.70-mm3/fs/ncpfs/mmap.c	2003-05-26 18:00:43.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/fs/ncpfs/mmap.c	2003-06-01 10:33:51.000000000 -0700
@@ -25,8 +25,8 @@
 /*
  * Fill in the supplied page for mmap
  */
-static struct page* ncp_file_mmap_nopage(struct vm_area_struct *area,
-				     unsigned long address, int write_access)
+static int ncp_file_mmap_nopage(struct mm_struct *mm, struct vm_area_struct *area,
+				unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	struct file *file = area->vm_file;
 	struct dentry *dentry = file->f_dentry;
@@ -38,6 +38,8 @@
 	int bufsize;
 	int pos;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	page = alloc_page(GFP_HIGHUSER); /* ncpfs has nothing against high pages
 	           as long as recvmsg and memset works on it */
 	if (!page)
@@ -85,7 +87,7 @@
 		memset(pg_addr + already_read, 0, PAGE_SIZE - already_read);
 	flush_dcache_page(page);
 	kunmap(page);
-	return page;
+	return install_new_page(mm, area, address, write_access, pmd, page);
 }
 
 static struct vm_operations_struct ncp_file_mmap =
diff -urN -X dontdiff linux-2.5.70-mm3/include/linux/mm.h linux-2.5.70-mm3.install_new_page_hch/include/linux/mm.h
--- linux-2.5.70-mm3/include/linux/mm.h	2003-05-31 16:31:20.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/include/linux/mm.h	2003-06-01 11:02:08.000000000 -0700
@@ -142,7 +142,7 @@
 struct vm_operations_struct {
 	void (*open)(struct vm_area_struct * area);
 	void (*close)(struct vm_area_struct * area);
-	struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int unused);
+	int (*nopage)(struct mm_struct * mm, struct vm_area_struct * area, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd);
 	int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
 };
 
@@ -380,12 +380,6 @@
 }
 
 /*
- * Error return values for the *_nopage functions
- */
-#define NOPAGE_SIGBUS	(NULL)
-#define NOPAGE_OOM	((struct page *) (-1))
-
-/*
  * Different kinds of faults, as returned by handle_mm_fault().
  * Used to decide whether a process gets delivered SIGBUS or
  * just gets major/minor fault counters bumped up.
@@ -402,8 +396,8 @@
 
 extern void show_free_areas(void);
 
-struct page *shmem_nopage(struct vm_area_struct * vma,
-			unsigned long address, int unused);
+int shmem_nopage(struct mm_struct * mm, struct vm_area_struct * vma,
+		 unsigned long address, int write_access, pte_t * page_table, pmd_t * pmd);
 struct file *shmem_file_setup(char * name, loff_t size, unsigned long flags);
 void shmem_lock(struct file * file, int lock);
 int shmem_zero_setup(struct vm_area_struct *);
@@ -421,6 +415,7 @@
 int zeromap_page_range(struct vm_area_struct *vma, unsigned long from,
 			unsigned long size, pgprot_t prot);
 
+extern int install_new_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access, pmd_t *pmd, struct page * new_page);
 extern void invalidate_mmap_range(struct address_space *mapping,
 				  loff_t const holebegin,
 				  loff_t const holelen);
@@ -559,7 +554,8 @@
 extern void truncate_inode_pages(struct address_space *, loff_t);
 
 /* generic vm_area_ops exported for stackable file systems */
-extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int);
+int filemap_nopage(struct mm_struct *, struct vm_area_struct *, unsigned long, int, pte_t *, pmd_t *);
+int do_anonymous_page(struct mm_struct *, struct vm_area_struct *, unsigned long, int, pte_t *, pmd_t *);
 
 /* mm/page-writeback.c */
 int write_one_page(struct page *page, int wait);
diff -urN -X dontdiff linux-2.5.70-mm3/kernel/ksyms.c linux-2.5.70-mm3.install_new_page_hch/kernel/ksyms.c
--- linux-2.5.70-mm3/kernel/ksyms.c	2003-05-31 16:31:20.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/kernel/ksyms.c	2003-05-31 16:39:23.000000000 -0700
@@ -116,6 +116,7 @@
 EXPORT_SYMBOL(max_mapnr);
 #endif
 EXPORT_SYMBOL(high_memory);
+EXPORT_SYMBOL(install_new_page);
 EXPORT_SYMBOL(invalidate_mmap_range);
 EXPORT_SYMBOL(vmtruncate);
 EXPORT_SYMBOL(find_vma);
diff -urN -X dontdiff linux-2.5.70-mm3/mm/filemap.c linux-2.5.70-mm3.install_new_page_hch/mm/filemap.c
--- linux-2.5.70-mm3/mm/filemap.c	2003-05-31 16:31:21.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/mm/filemap.c	2003-06-01 10:34:52.000000000 -0700
@@ -1013,7 +1013,7 @@
  * it in the page cache, and handles the special cases reasonably without
  * having a lot of duplicated code.
  */
-struct page * filemap_nopage(struct vm_area_struct * area, unsigned long address, int unused)
+int filemap_nopage(struct mm_struct * mm, struct vm_area_struct * area, unsigned long address, int write_access, pte_t *page_table, pmd_t * pmd)
 {
 	int error;
 	struct file *file = area->vm_file;
@@ -1024,6 +1024,8 @@
 	unsigned long size, pgoff, endoff;
 	int did_readahead;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	pgoff = ((address - area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
 	endoff = ((area->vm_end - area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
 
@@ -1034,7 +1036,7 @@
 	 */
 	size = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 	if ((pgoff >= size) && (area->vm_mm == current->mm))
-		return NULL;
+		return VM_FAULT_SIGBUS;
 
 	/*
 	 * The "size" of the file, as far as mmap is concerned, isn't bigger
@@ -1088,7 +1090,7 @@
 	 * Found the page and have a reference on it.
 	 */
 	mark_page_accessed(page);
-	return page;
+	return install_new_page(mm, area, address, write_access, pmd, page);
 
 no_cached_page:
 	/*
@@ -1111,8 +1113,8 @@
 	 * to schedule I/O.
 	 */
 	if (error == -ENOMEM)
-		return NOPAGE_OOM;
-	return NULL;
+		return VM_FAULT_OOM;
+	return VM_FAULT_SIGBUS;
 
 page_not_uptodate:
 	inc_page_state(pgmajfault);
@@ -1169,7 +1171,7 @@
 	 * mm layer so, possibly freeing the page cache page first.
 	 */
 	page_cache_release(page);
-	return NULL;
+	return VM_FAULT_SIGBUS;
 }
 
 static struct page * filemap_getpage(struct file *file, unsigned long pgoff,
diff -urN -X dontdiff linux-2.5.70-mm3/mm/memory.c linux-2.5.70-mm3.install_new_page_hch/mm/memory.c
--- linux-2.5.70-mm3/mm/memory.c	2003-05-31 16:31:21.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/mm/memory.c	2003-06-01 11:00:33.000000000 -0700
@@ -1304,10 +1304,10 @@
  * spinlock held to protect against concurrent faults in
  * multithreaded programs. 
  */
-static int
+int
 do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		pte_t *page_table, pmd_t *pmd, int write_access,
-		unsigned long addr)
+		  unsigned long addr, int write_access,
+		  pte_t *page_table, pmd_t *pmd)
 {
 	pte_t entry;
 	struct page * page = ZERO_PAGE(addr);
@@ -1374,40 +1374,19 @@
 }
 
 /*
- * do_no_page() tries to create a new page mapping. It aggressively
- * tries to share with existing pages, but makes a separate copy if
- * the "write_access" parameter is true in order to avoid the next
- * page fault.
- *
+ * install_new_page - tries to create a new page mapping.
+ * install_new_page() tries to share w/existing pages, but makes separate
+ * copy if "write_access" is true in order to avoid the next page fault.
  * As this is called only for pages that do not currently exist, we
  * do not need to flush old virtual caches or the TLB.
- *
- * This is called with the MM semaphore held and the page table
- * spinlock held. Exit with the spinlock released.
  */
-static int
-do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
-	unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
+int
+install_new_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access, pmd_t *pmd, struct page * new_page)
 {
-	struct page * new_page;
-	pte_t entry;
+	pte_t entry, *page_table;
 	struct pte_chain *pte_chain;
 	int ret;
 
-	if (!vma->vm_ops || !vma->vm_ops->nopage)
-		return do_anonymous_page(mm, vma, page_table,
-					pmd, write_access, address);
-	pte_unmap(page_table);
-	spin_unlock(&mm->page_table_lock);
-
-	new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, 0);
-
-	/* no page was available -- either SIGBUS or OOM */
-	if (new_page == NOPAGE_SIGBUS)
-		return VM_FAULT_SIGBUS;
-	if (new_page == NOPAGE_OOM)
-		return VM_FAULT_OOM;
-
 	pte_chain = pte_chain_alloc(GFP_KERNEL);
 	if (!pte_chain)
 		goto oom;
@@ -1490,7 +1469,7 @@
 	if (!vma->vm_ops || !vma->vm_ops->populate || 
 			(write_access && !(vma->vm_flags & VM_SHARED))) {
 		pte_clear(pte);
-		return do_no_page(mm, vma, address, write_access, pte, pmd);
+		return vma->vm_ops->nopage(mm, vma, address & PAGE_MASK, write_access, pte, pmd);
 	}
 
 	pgoff = pte_to_pgoff(*pte);
@@ -1541,7 +1520,7 @@
 		 * drop the lock.
 		 */
 		if (pte_none(entry))
-			return do_no_page(mm, vma, address, write_access, pte, pmd);
+			return vma->vm_ops->nopage(mm, vma, address & PAGE_MASK, write_access, pte, pmd);
 		if (pte_file(entry))
 			return do_file_page(mm, vma, address, write_access, pte, pmd);
 		return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
diff -urN -X dontdiff linux-2.5.70-mm3/mm/shmem.c linux-2.5.70-mm3.install_new_page_hch/mm/shmem.c
--- linux-2.5.70-mm3/mm/shmem.c	2003-05-26 18:00:39.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/mm/shmem.c	2003-06-01 10:36:09.000000000 -0700
@@ -936,23 +936,25 @@
 	return error;
 }
 
-struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int unused)
+int shmem_nopage(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	struct inode *inode = vma->vm_file->f_dentry->d_inode;
 	struct page *page = NULL;
 	unsigned long idx;
 	int error;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	idx = (address - vma->vm_start) >> PAGE_SHIFT;
 	idx += vma->vm_pgoff;
 	idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
 
 	error = shmem_getpage(inode, idx, &page, SGP_CACHE);
 	if (error)
-		return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS;
+		return (error == -ENOMEM)? VM_FAULT_OOM: VM_FAULT_SIGBUS;
 
 	mark_page_accessed(page);
-	return page;
+	return install_new_page(mm, vma, address, write_access, pmd, page);
 }
 
 static int shmem_populate(struct vm_area_struct *vma,
diff -urN -X dontdiff linux-2.5.70-mm3/net/packet/af_packet.c linux-2.5.70-mm3.install_new_page_hch/net/packet/af_packet.c
--- linux-2.5.70-mm3/net/packet/af_packet.c	2003-05-31 16:31:23.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/net/packet/af_packet.c	2003-06-01 10:14:58.000000000 -0700
@@ -1523,6 +1523,7 @@
 static struct vm_operations_struct packet_mmap_ops = {
 	.open =	packet_mm_open,
 	.close =packet_mm_close,
+	.nopage = do_anonymous_page,
 };
 
 static void free_pg_vec(unsigned long *pg_vec, unsigned order, unsigned len)
diff -urN -X dontdiff linux-2.5.70-mm3/sound/core/pcm_native.c linux-2.5.70-mm3.install_new_page_hch/sound/core/pcm_native.c
--- linux-2.5.70-mm3/sound/core/pcm_native.c	2003-05-26 18:00:37.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/sound/core/pcm_native.c	2003-06-01 10:40:02.000000000 -0700
@@ -60,6 +60,11 @@
 static int snd_pcm_hw_refine_old_user(snd_pcm_substream_t * substream, struct sndrv_pcm_hw_params_old * _oparams);
 static int snd_pcm_hw_params_old_user(snd_pcm_substream_t * substream, struct sndrv_pcm_hw_params_old * _oparams);
 
+#ifndef LINUX_2_2
+#define NOPAGE_OOM VM_FAULT_OOM
+#define NOPAGE_SIGBUS VM_FAULT_SIGBUS
+#endif
+
 /*
  *
  */
@@ -2693,7 +2698,7 @@
 #endif
 
 #ifndef LINUX_2_2
-static struct page * snd_pcm_mmap_status_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
+static int snd_pcm_mmap_status_nopage(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 #else
 static unsigned long snd_pcm_mmap_status_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
 #endif
@@ -2702,13 +2707,17 @@
 	snd_pcm_runtime_t *runtime;
 	struct page * page;
 	
+#ifndef LINUX_2_2
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
+#endif
 	if (substream == NULL)
 		return NOPAGE_OOM;
 	runtime = substream->runtime;
 	page = virt_to_page(runtime->status);
 	get_page(page);
 #ifndef LINUX_2_2
-	return page;
+	return install_new_page(mm, area, address, write_access, pmd, page);
 #else
 	return page_address(page);
 #endif
@@ -2747,7 +2756,7 @@
 }
 
 #ifndef LINUX_2_2
-static struct page * snd_pcm_mmap_control_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
+static int snd_pcm_mmap_control_nopage(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 #else
 static unsigned long snd_pcm_mmap_control_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
 #endif
@@ -2755,14 +2764,18 @@
 	snd_pcm_substream_t *substream = (snd_pcm_substream_t *)area->vm_private_data;
 	snd_pcm_runtime_t *runtime;
 	struct page * page;
-	
+
+#ifndef LINUX_2_2
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
+#endif
 	if (substream == NULL)
 		return NOPAGE_OOM;
 	runtime = substream->runtime;
 	page = virt_to_page(runtime->control);
 	get_page(page);
 #ifndef LINUX_2_2
-	return page;
+	return install_new_page(mm, area, address, write_access, pmd, page);
 #else
 	return page_address(page);
 #endif
@@ -2813,7 +2826,7 @@
 }
 
 #ifndef LINUX_2_2
-static struct page * snd_pcm_mmap_data_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
+static int snd_pcm_mmap_data_nopage(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 #else
 static unsigned long snd_pcm_mmap_data_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
 #endif
@@ -2824,7 +2837,11 @@
 	struct page * page;
 	void *vaddr;
 	size_t dma_bytes;
-	
+
+#ifndef LINUX_2_2
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
+#endif
 	if (substream == NULL)
 		return NOPAGE_OOM;
 	runtime = substream->runtime;
@@ -2848,7 +2865,7 @@
 	}
 	get_page(page);
 #ifndef LINUX_2_2
-	return page;
+	return install_new_page(mm, area, address, write_access, pmd, page);
 #else
 	return page_address(page);
 #endif
diff -urN -X dontdiff linux-2.5.70-mm3/sound/oss/emu10k1/audio.c linux-2.5.70-mm3.install_new_page_hch/sound/oss/emu10k1/audio.c
--- linux-2.5.70-mm3/sound/oss/emu10k1/audio.c	2003-05-26 18:00:23.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/sound/oss/emu10k1/audio.c	2003-06-01 10:42:22.000000000 -0700
@@ -970,7 +970,7 @@
 	return 0;
 }
 
-static struct page *emu10k1_mm_nopage (struct vm_area_struct * vma, unsigned long address, int write_access)
+static int emu10k1_mm_nopage (struct mm_struct * mm, struct vm_area_struct * vma, unsigned long address, int write_access, pte_t * page_table, pmd_t * pmd)
 {
 	struct emu10k1_wavedevice *wave_dev = vma->vm_private_data;
 	struct woinst *woinst = wave_dev->woinst;
@@ -979,12 +979,14 @@
 	unsigned long pgoff;
 	int rd, wr;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	DPF(3, "emu10k1_mm_nopage()\n");
 	DPD(3, "addr: %#lx\n", address);
 
 	if (address > vma->vm_end) {
-		DPF(1, "EXIT, returning NOPAGE_SIGBUS\n");
-		return NOPAGE_SIGBUS; /* Disallow mremap */
+		DPF(1, "EXIT, returning VM_FAULT_SIGBUS\n");
+		return VM_FAULT_SIGBUS; /* Disallow mremap */
 	}
 
 	pgoff = vma->vm_pgoff + ((address - vma->vm_start) >> PAGE_SHIFT);
@@ -1013,7 +1015,7 @@
 	get_page (dmapage);
 
 	DPD(3, "page: %#lx\n", (unsigned long) dmapage);
-	return dmapage;
+	return install_new_page(mm, vma, address, write_access, pmd, dmapage);
 }
 
 struct vm_operations_struct emu10k1_mm_ops = {
diff -urN -X dontdiff linux-2.5.70-mm3/sound/oss/via82cxxx_audio.c linux-2.5.70-mm3.install_new_page_hch/sound/oss/via82cxxx_audio.c
--- linux-2.5.70-mm3/sound/oss/via82cxxx_audio.c	2003-05-26 18:00:27.000000000 -0700
+++ linux-2.5.70-mm3.install_new_page_hch/sound/oss/via82cxxx_audio.c	2003-06-01 10:41:07.000000000 -0700
@@ -1846,8 +1846,8 @@
 }
 
 
-static struct page * via_mm_nopage (struct vm_area_struct * vma,
-				    unsigned long address, int write_access)
+static int via_mm_nopage (struct mm_struct *mm, struct vm_area_struct * vma,
+			  unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
 {
 	struct via_info *card = vma->vm_private_data;
 	struct via_channel *chan = &card->ch_out;
@@ -1855,6 +1855,8 @@
 	unsigned long pgoff;
 	int rd, wr;
 
+	pte_unmap(page_table);
+	spin_unlock(&mm->page_table_lock);
 	DPRINTK ("ENTER, start %lXh, ofs %lXh, pgoff %ld, addr %lXh, wr %d\n",
 		 vma->vm_start,
 		 address - vma->vm_start,
@@ -1863,12 +1865,12 @@
 		 write_access);
 
         if (address > vma->vm_end) {
-		DPRINTK ("EXIT, returning NOPAGE_SIGBUS\n");
-		return NOPAGE_SIGBUS; /* Disallow mremap */
+		DPRINTK ("EXIT, returning VM_FAULT_SIGBUS\n");
+		return VM_FAULT_SIGBUS; /* Disallow mremap */
 	}
         if (!card) {
-		DPRINTK ("EXIT, returning NOPAGE_OOM\n");
-		return NOPAGE_OOM;	/* Nothing allocated */
+		DPRINTK ("EXIT, returning VM_FAULT_OOM\n");
+		return VM_FAULT_OOM;	/* Nothing allocated */
 	}
 
 	pgoff = vma->vm_pgoff + ((address - vma->vm_start) >> PAGE_SHIFT);
@@ -1895,10 +1897,10 @@
 	assert ((((unsigned long)chan->pgtbl[pgoff].cpuaddr) % PAGE_SIZE) == 0);
 
 	dmapage = virt_to_page (chan->pgtbl[pgoff].cpuaddr);
-	DPRINTK ("EXIT, returning page %p for cpuaddr %lXh\n",
+	DPRINTK ("EXIT, installing page %p for cpuaddr %lXh\n",
 		 dmapage, (unsigned long) chan->pgtbl[pgoff].cpuaddr);
 	get_page (dmapage);
-	return dmapage;
+	return install_new_page(mm, vma, address, write_access, pmd, dmapage);
 }
 
 
--
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