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

Paul E. McKenney
2003-05-23T14:35:00Z

On Tue, May 20, 2003 at 01:11:57AM -0700, Andrew Morton wrote:
> "Paul E. McKenney" <paulmck@us.ibm.com> wrote:
> >
> > So the general idea is to do something as follows, right?
>
> It sounds reasonable. A matter of putting together the appropriate
> library functions and refactoring a few things.
>
> >
> > o Make a function, perhaps named something like
> > install_new_page(), that does the PTE-installation
> > and RSS-adjustment tasks currently performed by
> > both do_no_page() and by do_anonymous_page().
>
> That's similar to mm/fremap.c:install_page(). (Which forgets to call
> update_mmu_cache(). Debatably a buglet.)
>
> However there is not a lot of commonality between the various nopage()s and
> there may not be a lot to be gained from all this. There is subtle code in
> there and it is performance-critical. I'd be inclined to try to minimise
> overall code churn in this work.

Good point! Here is a patch to do this. A "few" caveats:

o I have not tested this, in fact, I have only compiled
it for i386.

o The bit about removing checks for vm_ops==NULL and
making do_anonymous_page() be just another nopage
function turned out to be problematic, since the
do_anonymous_page() function wants page_table_lock
held, and the other nopage functions do not.
So I kept the NULL checks, since I was going to
need some anyway (I did -not- want to make every
nopage function have to explicitly drop page_table_lock).

I am especially interested in feedback on this point --
did I miss something here?

o I had to expand the trace of the nopage functions to
pass through the mm_struct and the pmd_t to the
new install_new_page() function.

o The nopage functions now return an int instead of
the old struct page*.

o NOPAGE_OOM and NOPAGE_SIGBUS are no more, since
one case just use VM_FAULT_OOM and VM_FAULT_SIGBUS
instead.

o I still need to remove some LINUX_2_2 stuff (thanks
to Dan Phillips for letting me know it was OK to
do so...).

o This patch is a bit long. Thoughts on how to break it up?

Thanx, Paul

diff -urN -X dontdiff linux-2.5.69-mm7/arch/ia64/ia32/binfmt_elf32.c linux-2.5.69-mm7.install_new_page/arch/ia64/ia32/binfmt_elf32.c
--- linux-2.5.69-mm7/arch/ia64/ia32/binfmt_elf32.c Tue May 20 09:10:43 2003
+++ linux-2.5.69-mm7.install_new_page/arch/ia64/ia32/binfmt_elf32.c Thu May 22 16:26:07 2003
@@ -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)
+struct 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-2.5.69-mm7/arch/sparc64/mm/hugetlbpage.c linux-2.5.69-mm7.install_new_page/arch/sparc64/mm/hugetlbpage.c
--- linux-2.5.69-mm7/arch/sparc64/mm/hugetlbpage.c Sun May 4 16:53:35 2003
+++ linux-2.5.69-mm7.install_new_page/arch/sparc64/mm/hugetlbpage.c Thu May 22 16:23:56 2003
@@ -633,11 +633,12 @@
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-2.5.69-mm7/drivers/char/agp/alpha-agp.c linux-2.5.69-mm7.install_new_page/drivers/char/agp/alpha-agp.c
--- linux-2.5.69-mm7/drivers/char/agp/alpha-agp.c Tue May 20 09:10:46 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/char/agp/alpha-agp.c Thu May 22 16:02:30 2003
@@ -11,9 +11,11 @@

#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 +25,15 @@
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-2.5.69-mm7/drivers/char/drm/drmP.h linux-2.5.69-mm7.install_new_page/drivers/char/drm/drmP.h
--- linux-2.5.69-mm7/drivers/char/drm/drmP.h Sun May 4 16:53:36 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/char/drm/drmP.h Thu May 22 16:15:52 2003
@@ -620,18 +620,26 @@
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-2.5.69-mm7/drivers/char/drm/drm_vm.h linux-2.5.69-mm7.install_new_page/drivers/char/drm/drm_vm.h
--- linux-2.5.69-mm7/drivers/char/drm/drm_vm.h Sun May 4 16:53:57 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/char/drm/drm_vm.h Thu May 22 15:09:40 2003
@@ -55,9 +55,11 @@
.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 +116,38 @@
DRM_DEBUG("baddr = 0x%lx page = 0x%p, offset = 0x%lx\n",
baddr, __va(agpmem->memory->memory[offset]), offset);

- 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 +226,11 @@
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 +239,9 @@
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 +251,14 @@
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 +269,9 @@
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 +280,7 @@
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-2.5.69-mm7/drivers/ieee1394/dma.c linux-2.5.69-mm7.install_new_page/drivers/ieee1394/dma.c
--- linux-2.5.69-mm7/drivers/ieee1394/dma.c Sun May 4 16:53:31 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/ieee1394/dma.c Thu May 22 16:16:07 2003
@@ -184,28 +184,28 @@

/* 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-2.5.69-mm7/drivers/media/video/video-buf.c linux-2.5.69-mm7.install_new_page/drivers/media/video/video-buf.c
--- linux-2.5.69-mm7/drivers/media/video/video-buf.c Tue May 20 09:10:50 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/media/video/video-buf.c Thu May 22 17:59:32 2003
@@ -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-2.5.69-mm7/drivers/scsi/sg.c linux-2.5.69-mm7.install_new_page/drivers/scsi/sg.c
--- linux-2.5.69-mm7/drivers/scsi/sg.c Tue May 20 09:10:57 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/scsi/sg.c Thu May 22 16:34:00 2003
@@ -1121,21 +1121,22 @@
}
}

-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 +1163,7 @@
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-2.5.69-mm7/drivers/sgi/char/graphics.c linux-2.5.69-mm7.install_new_page/drivers/sgi/char/graphics.c
--- linux-2.5.69-mm7/drivers/sgi/char/graphics.c Sun May 4 16:53:31 2003
+++ linux-2.5.69-mm7.install_new_page/drivers/sgi/char/graphics.c Thu May 22 16:37:00 2003
@@ -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-2.5.69-mm7/fs/ncpfs/mmap.c linux-2.5.69-mm7.install_new_page/fs/ncpfs/mmap.c
--- linux-2.5.69-mm7/fs/ncpfs/mmap.c Sun May 4 16:53:35 2003
+++ linux-2.5.69-mm7.install_new_page/fs/ncpfs/mmap.c Thu May 22 16:28:25 2003
@@ -25,8 +25,10 @@
/*
* 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 +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-2.5.69-mm7/include/linux/mm.h linux-2.5.69-mm7.install_new_page/include/linux/mm.h
--- linux-2.5.69-mm7/include/linux/mm.h Tue May 20 09:11:08 2003
+++ linux-2.5.69-mm7.install_new_page/include/linux/mm.h Thu May 22 20:00:41 2003
@@ -142,7 +142,8 @@
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 +381,6 @@
}

/*
- * 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 +397,8 @@

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 +416,9 @@
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 +557,8 @@
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, pmd_t *);

/* mm/page-writeback.c */
int write_one_page(struct page *page, int wait);
diff -urN -X dontdiff linux-2.5.69-mm7/kernel/ksyms.c linux-2.5.69-mm7.install_new_page/kernel/ksyms.c
--- linux-2.5.69-mm7/kernel/ksyms.c Tue May 20 09:11:09 2003
+++ linux-2.5.69-mm7.install_new_page/kernel/ksyms.c Thu May 22 14:54:24 2003
@@ -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-2.5.69-mm7/mm/filemap.c linux-2.5.69-mm7.install_new_page/mm/filemap.c
--- linux-2.5.69-mm7/mm/filemap.c Tue May 20 09:11:09 2003
+++ linux-2.5.69-mm7.install_new_page/mm/filemap.c Thu May 22 19:55:56 2003
@@ -982,7 +982,8 @@
* 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;
@@ -1003,7 +1004,7 @@
*/
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
@@ -1057,7 +1058,7 @@
* 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:
/*
@@ -1080,8 +1081,8 @@
* 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);
@@ -1138,7 +1139,7 @@
* 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-2.5.69-mm7/mm/memory.c linux-2.5.69-mm7.install_new_page/mm/memory.c
--- linux-2.5.69-mm7/mm/memory.c Tue May 20 09:11:09 2003
+++ linux-2.5.69-mm7.install_new_page/mm/memory.c Thu May 22 14:56:27 2003
@@ -1385,28 +1385,49 @@
* This is called with the MM semaphore held and the page table
* spinlock held. Exit with the spinlock released.
*/
-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);
+ 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);
+ return vma->vm_ops->nopage(mm, vma, address & PAGE_MASK,
+ write_access, pmd);
+}

- /* 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.
+ * @mm: mmap structure, locus of locking and RSS activity.
+ * @vma: the vm_area_struct controlling the virtual address at
+ * which the page fault occurred.
+ * @address: address of fault.
+ * @write_access: write access required.
+ * @pmd: PMD for faulting address.
+ * @page: physical page to satisfy fault.
+ *
+ * The install_new_page() function 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.
+ */
+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;
+ pte_t *page_table;
+ struct pte_chain *pte_chain;
+ int ret;

pte_chain = pte_chain_alloc(GFP_KERNEL);
if (!pte_chain)
diff -urN -X dontdiff linux-2.5.69-mm7/mm/shmem.c linux-2.5.69-mm7.install_new_page/mm/shmem.c
--- linux-2.5.69-mm7/mm/shmem.c Tue May 20 09:11:10 2003
+++ linux-2.5.69-mm7.install_new_page/mm/shmem.c Thu May 22 17:18:55 2003
@@ -936,7 +936,8 @@
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 +950,10 @@

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-2.5.69-mm7/sound/core/pcm_native.c linux-2.5.69-mm7.install_new_page/sound/core/pcm_native.c
--- linux-2.5.69-mm7/sound/core/pcm_native.c Sun May 4 16:53:09 2003
+++ linux-2.5.69-mm7.install_new_page/sound/core/pcm_native.c Thu May 22 20:07:04 2003
@@ -2693,7 +2693,7 @@
#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
@@ -2703,12 +2703,12 @@
struct page * page;

if (substream == NULL)
- return NOPAGE_OOM;
+ return VM_FAULT_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 +2747,7 @@
}

#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
@@ -2757,12 +2757,12 @@
struct page * page;

if (substream == NULL)
- return NOPAGE_OOM;
+ return VM_FAULT_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 +2813,7 @@
}

#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
@@ -2826,7 +2826,7 @@
size_t dma_bytes;

if (substream == NULL)
- return NOPAGE_OOM;
+ return VM_FAULT_OOM;
runtime = substream->runtime;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 3, 25)
offset = area->vm_pgoff << PAGE_SHIFT;
@@ -2834,21 +2834,21 @@
offset = area->vm_offset;
#endif
offset += address - area->vm_start;
- snd_assert((offset % PAGE_SIZE) == 0, return NOPAGE_OOM);
+ snd_assert((offset % PAGE_SIZE) == 0, return VM_FAULT_OOM);
dma_bytes = PAGE_ALIGN(runtime->dma_bytes);
if (offset > dma_bytes - PAGE_SIZE)
- return NOPAGE_SIGBUS;
+ return VM_FAULT_SIGBUS;
if (substream->ops->page) {
page = substream->ops->page(substream, offset);
if (! page)
- return NOPAGE_OOM;
+ return VM_FAULT_OOM;
} else {
vaddr = runtime->dma_area + offset;
page = virt_to_page(vaddr);
}
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-2.5.69-mm7/sound/oss/emu10k1/audio.c linux-2.5.69-mm7.install_new_page/sound/oss/emu10k1/audio.c
--- linux-2.5.69-mm7/sound/oss/emu10k1/audio.c Sun May 4 16:53:02 2003
+++ linux-2.5.69-mm7.install_new_page/sound/oss/emu10k1/audio.c Thu May 22 16:18:16 2003
@@ -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-2.5.69-mm7/sound/oss/via82cxxx_audio.c linux-2.5.69-mm7.install_new_page/sound/oss/via82cxxx_audio.c
--- linux-2.5.69-mm7/sound/oss/via82cxxx_audio.c Sun May 4 16:53:08 2003
+++ linux-2.5.69-mm7.install_new_page/sound/oss/via82cxxx_audio.c Thu May 22 17:48:25 2003
@@ -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);
}