Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Paul E. McKenney]

On Fri, May 23, 2003 at 06:47:31PM +0100, Hugh Dickins wrote:
> On Fri, 23 May 2003, Daniel Phillips wrote:
> > On Friday 23 May 2003 18:21, Hugh Dickins wrote:
> > > Sorry, I miss the point of this patch entirely.  At the moment it just
> > > looks like an unattractive rearrangement - the code churn akpm advised
> > > against - with no bearing on that vmtruncate race.  Please correct me.
> > 
> > This is all about supporting cross-host mmap (nice trick, huh?).  Yes, 
> > somebody should post a detailed rfc on that subject.
> 
> Ah, thanks - translated into terms that I can understand, so that
> some ->nopage() not yet in the tree could do something after the
> install_new_page() returns.  Hmm.  Can we be sure it's appropriate
> for install_new_page to drop mm->page_table_lock before it returns?

Exactly -- allows a ->nopage() to drop some lock to avoid races
between pagefault and either vmtruncate() or invalidate_mmap_range().
This race (from the cross-host mmap viewpoint) is described in:

    http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2

install_new_page() has to drop mm->page_table_lock() for the same
reason that the previous do_no_page() did.  In addition, dropping
the lock permits a ->nopage() to invoke things like zap_page_range()
which acquire mm->page_table_lock().

						Thanx, Paul

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Paul E. McKenney]

On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote:
> On Fri, May 23, 2003 at 06:47:31PM +0100, Hugh Dickins wrote:
> > On Fri, 23 May 2003, Daniel Phillips wrote:
> > > On Friday 23 May 2003 18:21, Hugh Dickins wrote:
> > > > Sorry, I miss the point of this patch entirely.  At the moment it just
> > > > looks like an unattractive rearrangement - the code churn akpm advised
> > > > against - with no bearing on that vmtruncate race.  Please correct me.
> > > 
> > > This is all about supporting cross-host mmap (nice trick, huh?).  Yes, 
> > > somebody should post a detailed rfc on that subject.
> > 
> > Ah, thanks - translated into terms that I can understand, so that
> > some ->nopage() not yet in the tree could do something after the
> > install_new_page() returns.  Hmm.  Can we be sure it's appropriate
> > for install_new_page to drop mm->page_table_lock before it returns?
> 
> Exactly -- allows a ->nopage() to drop some lock to avoid races
> between pagefault and either vmtruncate() or invalidate_mmap_range().
> This race (from the cross-host mmap viewpoint) is described in:
> 
>     http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2
> 
> install_new_page() has to drop mm->page_table_lock() for the same
> reason that the previous do_no_page() did.  In addition, dropping
> the lock permits a ->nopage() to invoke things like zap_page_range()
> which acquire mm->page_table_lock().

Rediffed for 2.5.70-mm1.  Some added lines of code due to following
the "#ifndef LINUX_2_2" in the sound system.  The patch in the following
email removes these #ifdefs on the off-chance that they are a
holdover rather than the sound system's way of maintaining
a single code base across all versions of Linux or some such.

					Thanx, Paul


diff -urN -x dontdiff linux-2.5.70-mm1/arch/ia64/ia32/binfmt_elf32.c linux-2.5.70-mm1.install_new_page/arch/ia64/ia32/binfmt_elf32.c
--- linux-2.5.70-mm1/arch/ia64/ia32/binfmt_elf32.c	2003-05-26 18:00:58.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/arch/ia64/ia32/binfmt_elf32.c	2003-05-28 20:17:42.000000000 -0700
@@ -56,13 +56,13 @@
 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, pmd_t *pmd)
 {
 	struct page *pg = ia32_shared_page[(address - vma->vm_start)/PAGE_SIZE];
 
 	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-mm1/arch/sparc64/mm/hugetlbpage.c linux-2.5.70-mm1.install_new_page/arch/sparc64/mm/hugetlbpage.c
--- linux-2.5.70-mm1/arch/sparc64/mm/hugetlbpage.c	2003-05-26 18:00:42.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/arch/sparc64/mm/hugetlbpage.c	2003-05-28 20:17:42.000000000 -0700
@@ -633,11 +633,11 @@
 	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, pmd_t * pmd)
 {
 	BUG();
-	return NULL;
+	return VM_FAULT_SIGBUS;
 }
 
 static struct vm_operations_struct hugetlb_vm_ops = {
diff -urN -x dontdiff linux-2.5.70-mm1/drivers/char/agp/alpha-agp.c linux-2.5.70-mm1.install_new_page/drivers/char/agp/alpha-agp.c
--- linux-2.5.70-mm1/drivers/char/agp/alpha-agp.c	2003-05-26 18:00:42.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/char/agp/alpha-agp.c	2003-05-28 20:37:38.000000000 -0700
@@ -11,9 +11,9 @@
 
 #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, pmd_t pmd)
 {
 	alpha_agp_info *agp = agp_bridge->dev_private_data;
 	dma_addr_t dma_addr;
@@ -23,14 +23,14 @@
 	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-mm1/drivers/char/drm/drmP.h linux-2.5.70-mm1.install_new_page/drivers/char/drm/drmP.h
--- linux-2.5.70-mm1/drivers/char/drm/drmP.h	2003-05-26 18:00:45.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/char/drm/drmP.h	2003-05-28 20:55:40.000000000 -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, pmd_t *pmd);
+extern int DRM(vm_shm_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			      unsigned long address,
+			      int write_access, pmd_t *pmd);
+extern int DRM(vm_dma_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			      unsigned long address,
+			      int write_access, pmd_t *pmd);
+extern int DRM(vm_sg_nopage)(struct mm_struct *mm, struct vm_area_struct *vma,
+			     unsigned long address,
+			     int write_access, 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-mm1/drivers/char/drm/drm_vm.h linux-2.5.70-mm1.install_new_page/drivers/char/drm/drm_vm.h
--- linux-2.5.70-mm1/drivers/char/drm/drm_vm.h	2003-05-26 18:01:02.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/char/drm/drm_vm.h	2003-05-28 20:57:19.000000000 -0700
@@ -55,9 +55,9 @@
 	.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, pmd_t *pmd)
 {
 #if __REALLY_HAVE_AGP
 	drm_file_t *priv  = vma->vm_file->private_data;
@@ -114,35 +114,35 @@
 			  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, 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 */
+	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 +221,9 @@
 	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, pmd_t *pmd)
 {
 	drm_file_t	 *priv	 = vma->vm_file->private_data;
 	drm_device_t	 *dev	 = priv->dev;
@@ -232,9 +232,9 @@
 	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 */
+	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 +244,12 @@
 	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, 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 +260,9 @@
 	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 */
+	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 +271,7 @@
 	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-mm1/drivers/ieee1394/dma.c linux-2.5.70-mm1.install_new_page/drivers/ieee1394/dma.c
--- linux-2.5.70-mm1/drivers/ieee1394/dma.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/ieee1394/dma.c	2003-05-28 20:39:31.000000000 -0700
@@ -184,28 +184,27 @@
 
 /* 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, 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;
 
 	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-mm1/drivers/media/video/video-buf.c linux-2.5.70-mm1.install_new_page/drivers/media/video/video-buf.c
--- linux-2.5.70-mm1/drivers/media/video/video-buf.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/media/video/video-buf.c	2003-05-28 20:17:42.000000000 -0700
@@ -979,21 +979,21 @@
  * 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, pmd_t pmd)
 {
 	struct page *page;
 
 	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-mm1/drivers/scsi/sg.c linux-2.5.70-mm1.install_new_page/drivers/scsi/sg.c
--- linux-2.5.70-mm1/drivers/scsi/sg.c	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/scsi/sg.c	2003-05-28 20:39:59.000000000 -0700
@@ -1121,21 +1121,21 @@
 	}
 }
 
-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, 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;
 
 	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 +1162,7 @@
 		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-mm1/drivers/sgi/char/graphics.c linux-2.5.70-mm1.install_new_page/drivers/sgi/char/graphics.c
--- linux-2.5.70-mm1/drivers/sgi/char/graphics.c	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/drivers/sgi/char/graphics.c	2003-05-28 20:17:42.000000000 -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, pmd_t *pmdpf)
 {
 	pgd_t *pgd; pmd_t *pmd; pte_t *pte; 
 	int board = GRAPHICS_CARD (vma->vm_dentry->d_inode->i_rdev);
@@ -249,7 +249,7 @@
 	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-mm1/fs/ncpfs/mmap.c linux-2.5.70-mm1.install_new_page/fs/ncpfs/mmap.c
--- linux-2.5.70-mm1/fs/ncpfs/mmap.c	2003-05-26 18:00:43.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/fs/ncpfs/mmap.c	2003-05-28 20:17:42.000000000 -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, pmd_t *pmd)
 {
 	struct file *file = area->vm_file;
 	struct dentry *dentry = file->f_dentry;
@@ -85,7 +85,7 @@
 		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-mm1/include/linux/mm.h linux-2.5.70-mm1.install_new_page/include/linux/mm.h
--- linux-2.5.70-mm1/include/linux/mm.h	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/include/linux/mm.h	2003-05-28 20:17:42.000000000 -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, 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, 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 +554,7 @@
 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, pmd_t *);
 
 /* mm/page-writeback.c */
 int write_one_page(struct page *page, int wait);
diff -urN -x dontdiff linux-2.5.70-mm1/kernel/ksyms.c linux-2.5.70-mm1.install_new_page/kernel/ksyms.c
--- linux-2.5.70-mm1/kernel/ksyms.c	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/kernel/ksyms.c	2003-05-28 20:17:42.000000000 -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-mm1/mm/filemap.c linux-2.5.70-mm1.install_new_page/mm/filemap.c
--- linux-2.5.70-mm1/mm/filemap.c	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/mm/filemap.c	2003-05-28 20:17:42.000000000 -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, pmd_t * pmd)
 {
 	int error;
 	struct file *file = area->vm_file;
@@ -1034,7 +1034,7 @@
 	 */
 	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 +1088,7 @@
 	 * 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 +1111,8 @@
 	 * 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 +1169,7 @@
 	 * 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-mm1/mm/memory.c linux-2.5.70-mm1.install_new_page/mm/memory.c
--- linux-2.5.70-mm1/mm/memory.c	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/mm/memory.c	2003-05-28 20:43:16.000000000 -0700
@@ -1374,39 +1374,33 @@
 }
 
 /*
- * 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.
- *
- * 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.
+ * do_no_page() invokes do_anonymous_page() or ->nopage, as appropriate.
+ * Called w/ MM sema and page_table_lock held, the latter released before exit.
  */
-static int
+static inline 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)
 {
-	struct page * new_page;
-	pte_t entry;
-	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);
+		return do_anonymous_page(mm, vma, page_table, pmd, write_access, address);
 	pte_unmap(page_table);
 	spin_unlock(&mm->page_table_lock);
+	return vma->vm_ops->nopage(mm, vma, address & PAGE_MASK, write_access, pmd);
+}
 
-	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;
+/*
+ * 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.
+ */
+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)
+{
+	pte_t entry, *page_table;
+	struct pte_chain *pte_chain;
+	int ret;
 
 	pte_chain = pte_chain_alloc(GFP_KERNEL);
 	if (!pte_chain)
diff -urN -x dontdiff linux-2.5.70-mm1/mm/shmem.c linux-2.5.70-mm1.install_new_page/mm/shmem.c
--- linux-2.5.70-mm1/mm/shmem.c	2003-05-26 18:00:39.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/mm/shmem.c	2003-05-28 20:17:42.000000000 -0700
@@ -936,7 +936,7 @@
 	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, pmd_t *pmd)
 {
 	struct inode *inode = vma->vm_file->f_dentry->d_inode;
 	struct page *page = NULL;
@@ -949,10 +949,10 @@
 
 	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-mm1/sound/core/pcm_native.c linux-2.5.70-mm1.install_new_page/sound/core/pcm_native.c
--- linux-2.5.70-mm1/sound/core/pcm_native.c	2003-05-26 18:00:37.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/sound/core/pcm_native.c	2003-05-28 21:39:45.000000000 -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, pmd_t *pmd)
 #else
 static unsigned long snd_pcm_mmap_status_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
 #endif
@@ -2708,7 +2713,7 @@
 	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 +2752,7 @@
 }
 
 #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, pmd_t *pmd)
 #else
 static unsigned long snd_pcm_mmap_control_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
 #endif
@@ -2762,7 +2767,7 @@
 	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 +2818,7 @@
 }
 
 #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, pmd_t *pmd)
 #else
 static unsigned long snd_pcm_mmap_data_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
 #endif
@@ -2848,7 +2853,7 @@
 	}
 	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-mm1/sound/oss/emu10k1/audio.c linux-2.5.70-mm1.install_new_page/sound/oss/emu10k1/audio.c
--- linux-2.5.70-mm1/sound/oss/emu10k1/audio.c	2003-05-26 18:00:23.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/sound/oss/emu10k1/audio.c	2003-05-28 20:17:42.000000000 -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, pmd_t * pmd)
 {
 	struct emu10k1_wavedevice *wave_dev = vma->vm_private_data;
 	struct woinst *woinst = wave_dev->woinst;
@@ -983,8 +983,8 @@
 	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 +1013,7 @@
 	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-mm1/sound/oss/via82cxxx_audio.c linux-2.5.70-mm1.install_new_page/sound/oss/via82cxxx_audio.c
--- linux-2.5.70-mm1/sound/oss/via82cxxx_audio.c	2003-05-26 18:00:27.000000000 -0700
+++ linux-2.5.70-mm1.install_new_page/sound/oss/via82cxxx_audio.c	2003-05-28 20:17:44.000000000 -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, pmd_t *pmd)
 {
 	struct via_info *card = vma->vm_private_data;
 	struct via_channel *chan = &card->ch_out;
@@ -1863,12 +1863,12 @@
 		 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 +1895,10 @@
 	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);
 }
 
 

[RFC][PATCH] Remove LINUX_2_2

[Paul E. McKenney]

On Thu, May 29, 2003 at 08:14:24AM -0700, Paul E. McKenney wrote:
> Rediffed for 2.5.70-mm1.  Some added lines of code due to following
> the "#ifndef LINUX_2_2" in the sound system.  The patch in the following
> email removes these #ifdefs on the off-chance that they are a
> holdover rather than the sound system's way of maintaining
> a single code base across all versions of Linux or some such.

This is the patch to remove the LINUX_2_2.  This patch depends
on the earlier install_new_page.2.5.70-mm1-3.patch sent earlier.

 					Thanx, Paul


diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/control.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/control.c
--- linux-2.5.70-mm1.install_new_page/sound/core/control.c	2003-05-26 18:00:24.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/control.c	2003-05-28 22:41:51.000000000 -0700
@@ -931,9 +931,7 @@
 
 static struct file_operations snd_ctl_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		snd_ctl_read,
 	.open =		snd_ctl_open,
 	.release =	snd_ctl_release,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/hwdep.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/hwdep.c
--- linux-2.5.70-mm1.install_new_page/sound/core/hwdep.c	2003-05-26 18:00:21.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/hwdep.c	2003-05-28 22:41:51.000000000 -0700
@@ -292,9 +292,7 @@
 
 static struct file_operations snd_hwdep_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner = 	THIS_MODULE,
-#endif
 	.llseek =	snd_hwdep_llseek,
 	.read = 	snd_hwdep_read,
 	.write =	snd_hwdep_write,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/info.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/info.c
--- linux-2.5.70-mm1.install_new_page/sound/core/info.c	2003-05-26 18:00:59.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/info.c	2003-05-28 22:41:51.000000000 -0700
@@ -126,27 +126,6 @@
 snd_info_entry_t *snd_oss_root = NULL;
 #endif
 
-#ifdef LINUX_2_2
-static void snd_info_fill_inode(struct inode *inode, int fill)
-{
-	if (fill)
-		MOD_INC_USE_COUNT;
-	else
-		MOD_DEC_USE_COUNT;
-}
-
-static inline void snd_info_entry_prepare(struct proc_dir_entry *de)
-{
-	de->fill_inode = snd_info_fill_inode;
-}
-
-void snd_remove_proc_entry(struct proc_dir_entry *parent,
-			   struct proc_dir_entry *de)
-{
-	if (parent && de)
-		proc_unregister(parent, de->low_ino);
-}
-#else
 static inline void snd_info_entry_prepare(struct proc_dir_entry *de)
 {
 	de->owner = THIS_MODULE;
@@ -158,7 +137,6 @@
 	if (de)
 		remove_proc_entry(de->name, parent);
 }
-#endif
 
 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
 {
@@ -520,9 +498,7 @@
 
 static struct file_operations snd_info_entry_operations =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.llseek =	snd_info_entry_llseek,
 	.read =		snd_info_entry_read,
 	.write =	snd_info_entry_write,
@@ -533,67 +509,22 @@
 	.release =	snd_info_entry_release,
 };
 
-#ifdef LINUX_2_2
-static struct inode_operations snd_info_entry_inode_operations =
-{
-	&snd_info_entry_operations,	/* default sound info directory file-ops */
-};
-
-static struct inode_operations snd_info_device_inode_operations =
-{
-	&snd_fops,		/* default sound info directory file-ops */
-};
-#endif	/* LINUX_2_2 */
-
 static int snd_info_card_readlink(struct dentry *dentry,
 				  char *buffer, int buflen)
 {
         char *s = PDE(dentry->d_inode)->data;
-#ifndef LINUX_2_2
 	return vfs_readlink(dentry, buffer, buflen, s);
-#else
-	int len;
-	
-	if (s == NULL)
-		return -EIO;
-	len = strlen(s);
-	if (len > buflen)
-		len = buflen;
-	if (copy_to_user(buffer, s, len))
-		return -EFAULT;
-	return len;
-#endif
 }
 
-#ifndef LINUX_2_2
 static int snd_info_card_followlink(struct dentry *dentry,
 				    struct nameidata *nd)
 {
-        char *s = PDE(dentry->d_inode)->data;
-        return vfs_follow_link(nd, s);
-}
-#else
-static struct dentry *snd_info_card_followlink(struct dentry *dentry,
-					       struct dentry *base,
-					       unsigned int follow)
-{
 	char *s = PDE(dentry->d_inode)->data;
-	return lookup_dentry(s, base, follow);
+	return vfs_follow_link(nd, s);
 }
-#endif
-
-#ifdef LINUX_2_2
-static struct file_operations snd_info_card_link_operations =
-{
-	NULL
-};
-#endif
 
 struct inode_operations snd_info_card_link_inode_operations =
 {
-#ifdef LINUX_2_2
-	.default_file_ops =	&snd_info_card_link_operations,
-#endif
 	.readlink =		snd_info_card_readlink,
 	.follow_link =		snd_info_card_followlink,
 };
@@ -744,12 +675,8 @@
 	if (p == NULL)
 		return -ENOMEM;
 	p->data = s;
-#ifndef LINUX_2_2
 	p->owner = card->module;
 	p->proc_iops = &snd_info_card_link_inode_operations;
-#else
-	p->ops = &snd_info_card_link_inode_operations;
-#endif
 	card->proc_root_link = p;
 	return 0;
 }
@@ -1008,40 +935,11 @@
 	snd_magic_kfree(entry);
 }
 
-#ifdef LINUX_2_2
-static void snd_info_device_fill_inode(struct inode *inode, int fill)
-{
-	struct proc_dir_entry *de;
-	snd_info_entry_t *entry;
-
-	if (!fill) {
-		MOD_DEC_USE_COUNT;
-		return;
-	}
-	MOD_INC_USE_COUNT;
-	de = PDE(inode);
-	if (de == NULL)
-		return;
-	entry = (snd_info_entry_t *) de->data;
-	if (entry == NULL)
-		return;
-	inode->i_gid = device_gid;
-	inode->i_uid = device_uid;
-	inode->i_rdev = MKDEV(entry->c.device.major, entry->c.device.minor);
-}
-
-static inline void snd_info_device_entry_prepare(struct proc_dir_entry *de, snd_info_entry_t *entry)
-{
-	de->fill_inode = snd_info_device_fill_inode;
-	de->ops = &snd_info_device_inode_operations;
-}
-#else
 static inline void snd_info_device_entry_prepare(struct proc_dir_entry *de, snd_info_entry_t *entry)
 {
 	de->rdev = mk_kdev(entry->c.device.major, entry->c.device.minor);
 	de->owner = THIS_MODULE;
 }
-#endif /* LINUX_2_2 */
 
 /*
  * create a procfs device file
@@ -1119,15 +1017,9 @@
 		up(&info_mutex);
 		return -ENOMEM;
 	}
-#ifndef LINUX_2_2
 	p->owner = entry->module;
-#endif
 	if (!S_ISDIR(entry->mode)) {
-#ifndef LINUX_2_2
 		p->proc_fops = &snd_info_entry_operations;
-#else
-		p->ops = &snd_info_entry_inode_operations;
-#endif
 	}
 	p->size = entry->size;
 	p->data = entry;
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/init.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/init.c
--- linux-2.5.70-mm1.install_new_page/sound/core/init.c	2003-05-26 18:00:25.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/init.c	2003-05-28 22:41:51.000000000 -0700
@@ -193,9 +193,7 @@
 		f_ops = &s_f_ops->f_ops;
 
 		memset(f_ops, 0, sizeof(*f_ops));
-#ifndef LINUX_2_2
 		f_ops->owner = file->f_op->owner;
-#endif
 		f_ops->release = file->f_op->release;
 		f_ops->poll = snd_disconnect_poll;
 
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/oss/mixer_oss.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/oss/mixer_oss.c
--- linux-2.5.70-mm1.install_new_page/sound/core/oss/mixer_oss.c	2003-05-26 18:00:42.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/oss/mixer_oss.c	2003-05-28 22:41:51.000000000 -0700
@@ -376,9 +376,7 @@
 
 static struct file_operations snd_mixer_oss_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.open =		snd_mixer_oss_open,
 	.release =	snd_mixer_oss_release,
 	.ioctl =	snd_mixer_oss_ioctl,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/oss/pcm_oss.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/oss/pcm_oss.c
--- linux-2.5.70-mm1.install_new_page/sound/core/oss/pcm_oss.c	2003-05-26 18:00:56.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/oss/pcm_oss.c	2003-05-28 22:41:51.000000000 -0700
@@ -2148,9 +2148,7 @@
 
 static struct file_operations snd_pcm_oss_f_reg =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		snd_pcm_oss_read,
 	.write =	snd_pcm_oss_write,
 	.open =		snd_pcm_oss_open,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/pcm_native.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/pcm_native.c
--- linux-2.5.70-mm1.install_new_page/sound/core/pcm_native.c	2003-05-28 21:39:45.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/pcm_native.c	2003-05-28 22:46:38.000000000 -0700
@@ -60,11 +60,6 @@
 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
-
 /*
  *
  */
@@ -2687,21 +2682,13 @@
 }
 
 #ifndef VM_RESERVED
-#ifndef LINUX_2_2
 static int snd_pcm_mmap_swapout(struct page * page, struct file * file)
-#else
-static int snd_pcm_mmap_swapout(struct vm_area_struct * area, struct page * page)
-#endif
 {
 	return 0;
 }
 #endif
 
-#ifndef LINUX_2_2
 static int snd_pcm_mmap_status_nopage(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pmd_t *pmd)
-#else
-static unsigned long snd_pcm_mmap_status_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
-#endif
 {
 	snd_pcm_substream_t *substream = (snd_pcm_substream_t *)area->vm_private_data;
 	snd_pcm_runtime_t *runtime;
@@ -2712,11 +2699,7 @@
 	runtime = substream->runtime;
 	page = virt_to_page(runtime->status);
 	get_page(page);
-#ifndef LINUX_2_2
 	return install_new_page(mm, area, address, write_access, pmd, page);
-#else
-	return page_address(page);
-#endif
 }
 
 static struct vm_operations_struct snd_pcm_vm_ops_status =
@@ -2740,22 +2723,14 @@
 	if (size != PAGE_ALIGN(sizeof(snd_pcm_mmap_status_t)))
 		return -EINVAL;
 	area->vm_ops = &snd_pcm_vm_ops_status;
-#ifndef LINUX_2_2
 	area->vm_private_data = substream;
-#else
-	area->vm_private_data = (long)substream;	
-#endif
 #ifdef VM_RESERVED
 	area->vm_flags |= VM_RESERVED;
 #endif
 	return 0;
 }
 
-#ifndef LINUX_2_2
 static int snd_pcm_mmap_control_nopage(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pmd_t *pmd)
-#else
-static unsigned long snd_pcm_mmap_control_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
-#endif
 {
 	snd_pcm_substream_t *substream = (snd_pcm_substream_t *)area->vm_private_data;
 	snd_pcm_runtime_t *runtime;
@@ -2766,11 +2741,7 @@
 	runtime = substream->runtime;
 	page = virt_to_page(runtime->control);
 	get_page(page);
-#ifndef LINUX_2_2
 	return install_new_page(mm, area, address, write_access, pmd, page);
-#else
-	return page_address(page);
-#endif
 }
 
 static struct vm_operations_struct snd_pcm_vm_ops_control =
@@ -2794,11 +2765,7 @@
 	if (size != PAGE_ALIGN(sizeof(snd_pcm_mmap_control_t)))
 		return -EINVAL;
 	area->vm_ops = &snd_pcm_vm_ops_control;
-#ifndef LINUX_2_2
 	area->vm_private_data = substream;
-#else
-	area->vm_private_data = (long)substream;	
-#endif
 #ifdef VM_RESERVED
 	area->vm_flags |= VM_RESERVED;
 #endif
@@ -2817,11 +2784,7 @@
 	atomic_dec(&substream->runtime->mmap_count);
 }
 
-#ifndef LINUX_2_2
 static int snd_pcm_mmap_data_nopage(struct mm_struct *mm, struct vm_area_struct *area, unsigned long address, int write_access, pmd_t *pmd)
-#else
-static unsigned long snd_pcm_mmap_data_nopage(struct vm_area_struct *area, unsigned long address, int no_share)
-#endif
 {
 	snd_pcm_substream_t *substream = (snd_pcm_substream_t *)area->vm_private_data;
 	snd_pcm_runtime_t *runtime;
@@ -2852,11 +2815,7 @@
 		page = virt_to_page(vaddr);
 	}
 	get_page(page);
-#ifndef LINUX_2_2
 	return install_new_page(mm, area, address, write_access, pmd, page);
-#else
-	return page_address(page);
-#endif
 }
 
 static struct vm_operations_struct snd_pcm_vm_ops_data =
@@ -2906,11 +2865,7 @@
 		return -EINVAL;
 
 	area->vm_ops = &snd_pcm_vm_ops_data;
-#ifndef LINUX_2_2
 	area->vm_private_data = substream;
-#else
-	area->vm_private_data = (long)substream;
-#endif
 #ifdef VM_RESERVED
 	area->vm_flags |= VM_RESERVED;
 #endif
@@ -3040,9 +2995,7 @@
  */
 
 static struct file_operations snd_pcm_f_ops_playback = {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.write =	snd_pcm_write,
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 3, 44)
 	.writev =	snd_pcm_writev,
@@ -3056,9 +3009,7 @@
 };
 
 static struct file_operations snd_pcm_f_ops_capture = {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		snd_pcm_read,
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 3, 44)
 	.readv =	snd_pcm_readv,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/rawmidi.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/rawmidi.c
--- linux-2.5.70-mm1.install_new_page/sound/core/rawmidi.c	2003-05-26 18:00:24.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/rawmidi.c	2003-05-28 22:41:51.000000000 -0700
@@ -1316,9 +1316,7 @@
 
 static struct file_operations snd_rawmidi_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		snd_rawmidi_read,
 	.write =	snd_rawmidi_write,
 	.open =		snd_rawmidi_open,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/seq/oss/seq_oss.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/seq/oss/seq_oss.c
--- linux-2.5.70-mm1.install_new_page/sound/core/seq/oss/seq_oss.c	2003-05-26 18:00:46.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/seq/oss/seq_oss.c	2003-05-28 22:41:51.000000000 -0700
@@ -194,9 +194,7 @@
 
 static struct file_operations seq_oss_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		odev_read,
 	.write =	odev_write,
 	.open =		odev_open,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/seq/seq_clientmgr.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/seq/seq_clientmgr.c
--- linux-2.5.70-mm1.install_new_page/sound/core/seq/seq_clientmgr.c	2003-05-26 18:00:24.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/seq/seq_clientmgr.c	2003-05-28 22:41:51.000000000 -0700
@@ -2454,9 +2454,7 @@
 
 static struct file_operations snd_seq_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		snd_seq_read,
 	.write =	snd_seq_write,
 	.open =		snd_seq_open,
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/seq/seq_memory.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/seq/seq_memory.c
--- linux-2.5.70-mm1.install_new_page/sound/core/seq/seq_memory.c	2003-05-26 18:00:23.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/seq/seq_memory.c	2003-05-28 22:41:51.000000000 -0700
@@ -235,18 +235,7 @@
 	while (pool->free == NULL && ! nonblock && ! pool->closing) {
 
 		spin_unlock(&pool->lock);
-#ifdef LINUX_2_2
-		/* change semaphore to allow other clients
-		   to access device file */
-		if (file)
-			up(&semaphore_of(file));
-#endif
 		interruptible_sleep_on(&pool->output_sleep);
-#ifdef LINUX_2_2
-		/* restore semaphore again */
-		if (file)
-			down(&semaphore_of(file));
-#endif
 		spin_lock(&pool->lock);
 		/* interrupted? */
 		if (signal_pending(current)) {
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/sound.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/sound.c
--- linux-2.5.70-mm1.install_new_page/sound/core/sound.c	2003-05-26 18:00:43.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/sound.c	2003-05-28 22:41:51.000000000 -0700
@@ -157,9 +157,7 @@
 
 struct file_operations snd_fops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.open =		snd_open
 };
 
diff -urN -X dontdiff linux-2.5.70-mm1.install_new_page/sound/core/timer.c linux-2.5.70-mm1.loseLINUX_2_2/sound/core/timer.c
--- linux-2.5.70-mm1.install_new_page/sound/core/timer.c	2003-05-26 18:00:41.000000000 -0700
+++ linux-2.5.70-mm1.loseLINUX_2_2/sound/core/timer.c	2003-05-28 22:41:51.000000000 -0700
@@ -1733,9 +1733,7 @@
 
 static struct file_operations snd_timer_f_ops =
 {
-#ifndef LINUX_2_2
 	.owner =	THIS_MODULE,
-#endif
 	.read =		snd_timer_user_read,
 	.open =		snd_timer_user_open,
 	.release =	snd_timer_user_release,

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Hugh Dickins]

On Thu, 29 May 2003, Paul E. McKenney wrote:
> On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote:
> > 
> > Exactly -- allows a ->nopage() to drop some lock to avoid races
> > between pagefault and either vmtruncate() or invalidate_mmap_range().
> > This race (from the cross-host mmap viewpoint) is described in:
> > 
> >     http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2
> 
> Rediffed for 2.5.70-mm1.

Me?  I much preferred your original, much sparer, nopagedone patch
(labelled "uglyh as hell" by hch).  I dislike passing lots of args
down a level so they can be passed up again to the library function.

In particular, I feel queasy (fear loss of control) about passing a
pmd_t* down to a filesystem, which I'd prefer to have no access to
such.  But I may be in a minority, and the decision won't be mine.

Hugh

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Daniel Phillips]

On Thursday 29 May 2003 18:33, you wrote:
> On Thu, 29 May 2003, Paul E. McKenney wrote:
> > On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote:
> > > Exactly -- allows a ->nopage() to drop some lock to avoid races
> > > between pagefault and either vmtruncate() or invalidate_mmap_range().
> > > This race (from the cross-host mmap viewpoint) is described in:
> > >
> > >     http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2
> >
> > Rediffed for 2.5.70-mm1.
>
> Me?  I much preferred your original, much sparer, nopagedone patch
> (labelled "uglyh as hell" by hch).

"me too".

The fat patch that hits every fs to get rid of two lines and .5 cycles per 
no_page fault could be an epilogue (if/when it passes muster) to the little 
one that does the job and has already been thoroughly tested.

I see both sides of the argument.  The third side, not yet discussed, is the 
value of doing things incrementally, with widespread testing of the system at 
each step.

Regards,

Daniel

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Daniel Phillips]

On Thursday 29 May 2003 19:15, Daniel Phillips wrote:
> On Thursday 29 May 2003 18:33, you wrote:
> > Me?  I much preferred your original, much sparer, nopagedone patch
> > (labelled "uglyh as hell" by hch).
>
> "me too".

Oh wait, I mispoke... there is another formulation of the patch that hasn't 
yet been posted for review.  Instead of having the nopagedone hook, it turns 
the entire do_no_page into a hook, per hch's suggestion, but leaves in the 
->nopage hook, which makes the patch small and obviously right.  I need to 
post that version for comparison, please bear with me.

IMHO, it's nicer than the ->nopagedone form.

Regards,

Daniel

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Paul E. McKenney]

On Thu, May 29, 2003 at 07:39:47PM +0200, Daniel Phillips wrote:
> On Thursday 29 May 2003 19:15, Daniel Phillips wrote:
> > On Thursday 29 May 2003 18:33, you wrote:
> > > Me?  I much preferred your original, much sparer, nopagedone patch
> > > (labelled "uglyh as hell" by hch).
> >
> > "me too".
> 
> Oh wait, I mispoke... there is another formulation of the patch that hasn't 
> yet been posted for review.  Instead of having the nopagedone hook, it turns 
> the entire do_no_page into a hook, per hch's suggestion, but leaves in the 
> ->nopage hook, which makes the patch small and obviously right.  I need to 
> post that version for comparison, please bear with me.
> 
> IMHO, it's nicer than the ->nopagedone form.

I put together something like this, but the problem with it is that
do_anonymous_page() needs the mm->page_table_lock held, but the
->nopage functions want this lock not to be held.  One could require
that all the lock be held on entry to all ->nopage functions, but
this would require almost all ->nopage functions to drop the lock
immediately upon entry.  This seemed error-prone to me, but could
certainly be done...

Thoughts?  Me, I don't care as long as there is some reasonable
way for distributed filesystems to safely resolve the race between
page faults and invalidation requests from other nodes.  ;-)

						Thanx, Paul

Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race

[Paul E. McKenney]

On Thu, May 29, 2003 at 05:33:04PM +0100, Hugh Dickins wrote:
> On Thu, 29 May 2003, Paul E. McKenney wrote:
> > On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote:
> > > 
> > > Exactly -- allows a ->nopage() to drop some lock to avoid races
> > > between pagefault and either vmtruncate() or invalidate_mmap_range().
> > > This race (from the cross-host mmap viewpoint) is described in:
> > > 
> > >     http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2
> > 
> > Rediffed for 2.5.70-mm1.
> 
> Me?  I much preferred your original, much sparer, nopagedone patch
> (labelled "uglyh as hell" by hch).  I dislike passing lots of args
> down a level so they can be passed up again to the library function.
> 
> In particular, I feel queasy (fear loss of control) about passing a
> pmd_t* down to a filesystem, which I'd prefer to have no access to
> such.  But I may be in a minority, and the decision won't be mine.

Fine by me either way.  ;-)  Here is the rediffed nopagedone patch
for 2.5.70-mm1.

						Thanx, Paul


diff -urN -X dontdiff linux-2.5.70-mm1/include/linux/mm.h linux-2.5.70-mm1.nopagedone/include/linux/mm.h
--- linux-2.5.70-mm1/include/linux/mm.h	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.nopagedone/include/linux/mm.h	2003-05-29 19:34:55.000000000 -0700
@@ -143,6 +143,7 @@
 	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);
+	void (*nopagedone)(struct vm_area_struct * area, unsigned long address, int status);
 	int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
 };
 
diff -urN -X dontdiff linux-2.5.70-mm1/mm/memory.c linux-2.5.70-mm1.nopagedone/mm/memory.c
--- linux-2.5.70-mm1/mm/memory.c	2003-05-28 20:16:04.000000000 -0700
+++ linux-2.5.70-mm1.nopagedone/mm/memory.c	2003-05-29 19:34:55.000000000 -0700
@@ -1468,6 +1468,9 @@
 	ret = VM_FAULT_OOM;
 out:
 	pte_chain_free(pte_chain);
+	if (vma->vm_ops && vma->vm_ops->nopagedone) {
+		vma->vm_ops->nopagedone(vma, address & PAGE_MASK, ret);
+	}
 	return ret;
 }