[patch 6/6] mm: core remove PageReserved (take 2)

From: Nick Piggin
Date: Tue Jul 26 2005 - 03:58:01 EST

Nick Piggin wrote:
6/6


Actually I think Hugh gave me some feedback about the introduced
`print_invalid_pfn` function, which I ignored.

So here is patch 6 again, with print_invalid_pfn renamed invalid_pfn,
and using a macro to alleviate the requirement of passing in the
function name by hand.

Remove PageReserved() calls from core code by tightening VM_RESERVED
handling in mm/ to cover PageReserved functionality.

PageReserved special casing is removed from get_page and put_page.

All setting and clearning of PageReserved is retained, and it is now
flagged in the page_alloc checks to help ensure we don't introduce
any refcount based freeing of Reserved pages.

MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
deprecated. We never completely handled it correctly anyway, and is
difficult to handle nicely - difficult but not impossible, it could
be reintroduced in future if required (Hugh has a proof of concept).

Once PageReserved() calls are removed from kernel/power/swsusp.c, and
all arch/ and driver code, the Set and Clear calls, and the PG_reserved
bit can be trivially removed.

Last real user of PageReserved is swsusp, which uses PageReserved to
determine whether a struct page points to valid memory or not. This
still needs to be addressed.

Many thanks to Hugh Dickins for input.

Signed-off-by: Nick Piggin <npiggin@xxxxxxx>


Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h
+++ linux-2.6/include/linux/mm.h
@@ -156,7 +156,8 @@ extern unsigned int kobjsize(const void

#define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */
#define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
-#define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */
+#define VM_RESERVED 0x00080000 /* Pages and ptes in region aren't managed with regular pagecache or rmap routines */
+
#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
@@ -337,7 +338,7 @@ static inline void get_page(struct page

static inline void put_page(struct page *page)
{
- if (!PageReserved(page) && put_page_testzero(page))
+ if (put_page_testzero(page))
__page_cache_release(page);
}

@@ -711,6 +712,9 @@ void install_arg_page(struct vm_area_str

int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
+#define invalid_pfn(pte, vm_flags, vaddr) \
+ __invalid_pfn(__FUNCTION__, pte, vm_flags, vaddr)
+void __invalid_pfn(const char *, pte_t, unsigned long, unsigned long);

int __set_page_dirty_buffers(struct page *page);
int __set_page_dirty_nobuffers(struct page *page);
Index: linux-2.6/mm/madvise.c
===================================================================
--- linux-2.6.orig/mm/madvise.c
+++ linux-2.6/mm/madvise.c
@@ -126,7 +126,7 @@ static long madvise_dontneed(struct vm_a
unsigned long start, unsigned long end)
{
*prev = vma;
- if ((vma->vm_flags & VM_LOCKED) || is_vm_hugetlb_page(vma))
+ if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) || is_vm_hugetlb_page(vma))
return -EINVAL;

if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c
+++ linux-2.6/mm/memory.c
@@ -333,6 +333,21 @@ out:
}

/*
+ * This function is called to print an error when a pte in a
+ * !VM_RESERVED region is found pointing to an invalid pfn (which
+ * is an error.
+ *
+ * The calling function must still handle the error.
+ */
+void __invalid_pfn(const char *errfunc, pte_t pte,
+ unsigned long vm_flags, unsigned long vaddr)
+{
+ printk(KERN_ERR "%s: pte does not point to valid memory. "
+ "process = %s, pte = %08lx, vm_flags = %lx, vaddr = %lx\n",
+ errfunc, current->comm, (long)pte_val(pte), vm_flags, vaddr);
+}
+
+/*
* copy one vm_area from one task to the other. Assumes the page tables
* already present in the new task to be cleared in the whole range
* covered by this vma.
@@ -361,25 +376,29 @@ copy_one_pte(struct mm_struct *dst_mm, s
spin_unlock(&mmlist_lock);
}
}
- set_pte_at(dst_mm, addr, dst_pte, pte);
- return;
+ goto out_set_pte;
}

+ /* If the region is VM_RESERVED, the mapping is not
+ * mapped via rmap - duplicate the pte as is.
+ */
+ if (vm_flags & VM_RESERVED)
+ goto out_set_pte;
+
+ /* If the pte points outside of valid memory but
+ * the region is not VM_RESERVED, we have a problem.
+ */
pfn = pte_pfn(pte);
- /* the pte points outside of valid memory, the
- * mapping is assumed to be good, meaningful
- * and not mapped via rmap - duplicate the
- * mapping as is.
- */
- page = NULL;
- if (pfn_valid(pfn))
- page = pfn_to_page(pfn);
-
- if (!page || PageReserved(page)) {
- set_pte_at(dst_mm, addr, dst_pte, pte);
- return;
+ if (unlikely(!pfn_valid(pfn))) {
+ invalid_pfn(pte, vm_flags, addr);
+ goto out_set_pte; /* try to do something sane */
}

+ page = pfn_to_page(pfn);
+ /* Mappings to zero pages aren't covered by rmap either. */
+ if (page == ZERO_PAGE(addr))
+ goto out_set_pte;
+
/*
* If it's a COW mapping, write protect it both
* in the parent and the child
@@ -400,8 +419,9 @@ copy_one_pte(struct mm_struct *dst_mm, s
inc_mm_counter(dst_mm, rss);
if (PageAnon(page))
inc_mm_counter(dst_mm, anon_rss);
- set_pte_at(dst_mm, addr, dst_pte, pte);
page_dup_rmap(page);
+out_set_pte:
+ set_pte_at(dst_mm, addr, dst_pte, pte);
}

static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
@@ -514,7 +534,8 @@ int copy_page_range(struct mm_struct *ds
return 0;
}

-static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
+static void zap_pte_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
struct zap_details *details)
{
@@ -528,10 +549,14 @@ static void zap_pte_range(struct mmu_gat
if (pte_present(ptent)) {
struct page *page = NULL;
unsigned long pfn = pte_pfn(ptent);
- if (pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- if (PageReserved(page))
- page = NULL;
+ if (!(vma->vm_flags & VM_RESERVED)) {
+ if (unlikely(!pfn_valid(pfn))) {
+ invalid_pfn(ptent, vma->vm_flags, addr);
+ } else {
+ page = pfn_to_page(pfn);
+ if (page == ZERO_PAGE(addr))
+ page = NULL;
+ }
}
if (unlikely(details) && page) {
/*
@@ -584,7 +609,8 @@ static void zap_pte_range(struct mmu_gat
pte_unmap(pte - 1);
}

-static inline void zap_pmd_range(struct mmu_gather *tlb, pud_t *pud,
+static inline void zap_pmd_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pud_t *pud,
unsigned long addr, unsigned long end,
struct zap_details *details)
{
@@ -596,11 +622,12 @@ static inline void zap_pmd_range(struct
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
- zap_pte_range(tlb, pmd, addr, next, details);
+ zap_pte_range(tlb, vma, pmd, addr, next, details);
} while (pmd++, addr = next, addr != end);
}

-static inline void zap_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
+static inline void zap_pud_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pgd_t *pgd,
unsigned long addr, unsigned long end,
struct zap_details *details)
{
@@ -612,7 +639,7 @@ static inline void zap_pud_range(struct
next = pud_addr_end(addr, end);
if (pud_none_or_clear_bad(pud))
continue;
- zap_pmd_range(tlb, pud, addr, next, details);
+ zap_pmd_range(tlb, vma, pud, addr, next, details);
} while (pud++, addr = next, addr != end);
}

@@ -633,7 +660,7 @@ static void unmap_page_range(struct mmu_
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
- zap_pud_range(tlb, pgd, addr, next, details);
+ zap_pud_range(tlb, vma, pgd, addr, next, details);
} while (pgd++, addr = next, addr != end);
tlb_end_vma(tlb, vma);
}
@@ -924,7 +951,7 @@ int get_user_pages(struct task_struct *t
continue;
}

- if (!vma || (vma->vm_flags & VM_IO)
+ if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
|| !(flags & vma->vm_flags))
return i ? : -EFAULT;

@@ -980,8 +1007,7 @@ int get_user_pages(struct task_struct *t
if (pages) {
pages[i] = page;
flush_dcache_page(page);
- if (!PageReserved(page))
- page_cache_get(page);
+ page_cache_get(page);
}
if (vmas)
vmas[i] = vma;
@@ -1085,8 +1111,7 @@ static int remap_pte_range(struct mm_str
return -ENOMEM;
do {
BUG_ON(!pte_none(*pte));
- if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
- set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
+ set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap(pte - 1);
@@ -1225,6 +1250,8 @@ static int do_wp_page(struct mm_struct *
unsigned long pfn = pte_pfn(pte);
pte_t entry;

+ BUG_ON(vma->vm_flags & VM_RESERVED);
+
if (unlikely(!pfn_valid(pfn))) {
/*
* This should really halt the system so it can be debugged or
@@ -1232,9 +1259,8 @@ static int do_wp_page(struct mm_struct *
* data, but for the moment just pretend this is OOM.
*/
pte_unmap(page_table);
- printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n",
- address);
spin_unlock(&mm->page_table_lock);
+ invalid_pfn(pte, vma->vm_flags, address);
return VM_FAULT_OOM;
}
old_page = pfn_to_page(pfn);
@@ -1259,13 +1285,16 @@ static int do_wp_page(struct mm_struct *
/*
* Ok, we need to copy. Oh, well..
*/
- if (!PageReserved(old_page))
+ if (old_page == ZERO_PAGE(address))
+ old_page = NULL;
+ else
page_cache_get(old_page);
+
spin_unlock(&mm->page_table_lock);

if (unlikely(anon_vma_prepare(vma)))
goto no_new_page;
- if (old_page == ZERO_PAGE(address)) {
+ if (old_page == NULL) {
new_page = alloc_zeroed_user_highpage(vma, address);
if (!new_page)
goto no_new_page;
@@ -1281,12 +1310,13 @@ static int do_wp_page(struct mm_struct *
spin_lock(&mm->page_table_lock);
page_table = pte_offset_map(pmd, address);
if (likely(pte_same(*page_table, pte))) {
- if (PageAnon(old_page))
- dec_mm_counter(mm, anon_rss);
- if (PageReserved(old_page))
+ if (old_page == NULL)
inc_mm_counter(mm, rss);
- else
+ else {
page_remove_rmap(old_page);
+ if (PageAnon(old_page))
+ dec_mm_counter(mm, anon_rss);
+ }
flush_cache_page(vma, address, pfn);
break_cow(vma, new_page, address, page_table);
lru_cache_add_active(new_page);
@@ -1296,13 +1326,16 @@ static int do_wp_page(struct mm_struct *
new_page = old_page;
}
pte_unmap(page_table);
- page_cache_release(new_page);
- page_cache_release(old_page);
spin_unlock(&mm->page_table_lock);
+ if (old_page) {
+ page_cache_release(new_page);
+ page_cache_release(old_page);
+ }
return VM_FAULT_MINOR;

no_new_page:
- page_cache_release(old_page);
+ if (old_page)
+ page_cache_release(old_page);
return VM_FAULT_OOM;
}

@@ -1739,7 +1772,7 @@ do_anonymous_page(struct mm_struct *mm,
struct page * page = ZERO_PAGE(addr);

/* Read-only mapping of ZERO_PAGE. */
- entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
+ entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));

/* ..except if it's a write access */
if (write_access) {
@@ -1878,9 +1911,6 @@ retry:
*/
/* Only go through if we didn't race with anybody else... */
if (pte_none(*page_table)) {
- if (!PageReserved(new_page))
- inc_mm_counter(mm, rss);
-
flush_icache_page(vma, new_page);
entry = mk_pte(new_page, vma->vm_page_prot);
if (write_access)
@@ -1889,8 +1919,10 @@ retry:
if (anon) {
lru_cache_add_active(new_page);
page_add_anon_rmap(new_page, vma, address);
- } else
+ } else if (!(vma->vm_flags & VM_RESERVED)) {
page_add_file_rmap(new_page);
+ inc_mm_counter(mm, rss);
+ }
pte_unmap(page_table);
} else {
/* One of our sibling threads was faster, back out. */
Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -113,7 +113,8 @@ static void bad_page(const char *functio
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
- 1 << PG_writeback);
+ 1 << PG_writeback |
+ 1 << PG_reserved );
set_page_count(page, 0);
reset_page_mapcount(page);
page->mapping = NULL;
@@ -243,7 +244,6 @@ static inline int page_is_buddy(struct p
{
if (PagePrivate(page) &&
(page_order(page) == order) &&
- !PageReserved(page) &&
page_count(page) == 0)
return 1;
return 0;
@@ -326,7 +326,8 @@ static inline void free_pages_check(cons
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
- 1 << PG_writeback )))
+ 1 << PG_writeback |
+ 1 << PG_reserved )))
bad_page(function, page);
if (PageDirty(page))
__ClearPageDirty(page);
@@ -454,7 +455,8 @@ static void prep_new_page(struct page *p
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
- 1 << PG_writeback )))
+ 1 << PG_writeback |
+ 1 << PG_reserved )))
bad_page(__FUNCTION__, page);

page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
@@ -1011,7 +1013,7 @@ void __pagevec_free(struct pagevec *pvec

fastcall void __free_pages(struct page *page, unsigned int order)
{
- if (!PageReserved(page) && put_page_testzero(page)) {
+ if (put_page_testzero(page)) {
if (order == 0)
free_hot_page(page);
else
@@ -1654,7 +1656,7 @@ void __init memmap_init_zone(unsigned lo
continue;
page = pfn_to_page(pfn);
set_page_links(page, zone, nid, pfn);
- set_page_count(page, 0);
+ set_page_count(page, 1);
reset_page_mapcount(page);
SetPageReserved(page);
INIT_LIST_HEAD(&page->lru);
Index: linux-2.6/mm/swap.c
===================================================================
--- linux-2.6.orig/mm/swap.c
+++ linux-2.6/mm/swap.c
@@ -48,7 +48,7 @@ void put_page(struct page *page)
}
return;
}
- if (!PageReserved(page) && put_page_testzero(page))
+ if (put_page_testzero(page))
__page_cache_release(page);
}
EXPORT_SYMBOL(put_page);
@@ -215,7 +215,7 @@ void release_pages(struct page **pages,
struct page *page = pages[i];
struct zone *pagezone;

- if (PageReserved(page) || !put_page_testzero(page))
+ if (!put_page_testzero(page))
continue;

pagezone = page_zone(page);
Index: linux-2.6/mm/fremap.c
===================================================================
--- linux-2.6.orig/mm/fremap.c
+++ linux-2.6/mm/fremap.c
@@ -29,18 +29,21 @@ static inline void zap_pte(struct mm_str
return;
if (pte_present(pte)) {
unsigned long pfn = pte_pfn(pte);
+ struct page *page;

flush_cache_page(vma, addr, pfn);
pte = ptep_clear_flush(vma, addr, ptep);
- if (pfn_valid(pfn)) {
- struct page *page = pfn_to_page(pfn);
- if (!PageReserved(page)) {
- if (pte_dirty(pte))
- set_page_dirty(page);
- page_remove_rmap(page);
- page_cache_release(page);
- dec_mm_counter(mm, rss);
- }
+ if (unlikely(!pfn_valid(pfn))) {
+ invalid_pfn(pte, vma->vm_flags, addr);
+ return;
+ }
+ page = pfn_to_page(pfn);
+ if (page != ZERO_PAGE(addr)) {
+ if (pte_dirty(pte))
+ set_page_dirty(page);
+ page_remove_rmap(page);
+ dec_mm_counter(mm, rss);
+ page_cache_release(page);
}
} else {
if (!pte_file(pte))
@@ -65,6 +68,8 @@ int install_page(struct mm_struct *mm, s
pgd_t *pgd;
pte_t pte_val;

+ BUG_ON(vma->vm_flags & VM_RESERVED);
+
pgd = pgd_offset(mm, addr);
spin_lock(&mm->page_table_lock);

@@ -122,6 +127,8 @@ int install_file_pte(struct mm_struct *m
pgd_t *pgd;
pte_t pte_val;

+ BUG_ON(vma->vm_flags & VM_RESERVED);
+
pgd = pgd_offset(mm, addr);
spin_lock(&mm->page_table_lock);

Index: linux-2.6/mm/msync.c
===================================================================
--- linux-2.6.orig/mm/msync.c
+++ linux-2.6/mm/msync.c
@@ -37,11 +37,11 @@ static void sync_pte_range(struct vm_are
if (!pte_maybe_dirty(*pte))
continue;
pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn))
+ if (unlikely(!pfn_valid(pfn))) {
+ invalid_pfn(*pte, vma->vm_flags, addr);
continue;
+ }
page = pfn_to_page(pfn);
- if (PageReserved(page))
- continue;

if (ptep_clear_flush_dirty(vma, addr, pte) ||
page_test_and_clear_dirty(page))
@@ -149,6 +149,9 @@ static int msync_interval(struct vm_area
if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
return -EBUSY;

+ if (vma->vm_flags & VM_RESERVED)
+ return -EINVAL;
+
if (file && (vma->vm_flags & VM_SHARED)) {
filemap_sync(vma, addr, end);

Index: linux-2.6/mm/rmap.c
===================================================================
--- linux-2.6.orig/mm/rmap.c
+++ linux-2.6/mm/rmap.c
@@ -442,8 +442,6 @@ int page_referenced(struct page *page, i
void page_add_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address)
{
- BUG_ON(PageReserved(page));
-
inc_mm_counter(vma->vm_mm, anon_rss);

if (atomic_inc_and_test(&page->_mapcount)) {
@@ -469,8 +467,7 @@ void page_add_anon_rmap(struct page *pag
void page_add_file_rmap(struct page *page)
{
BUG_ON(PageAnon(page));
- if (!pfn_valid(page_to_pfn(page)) || PageReserved(page))
- return;
+ BUG_ON(!pfn_valid(page_to_pfn(page)));

if (atomic_inc_and_test(&page->_mapcount))
inc_page_state(nr_mapped);
@@ -484,8 +481,6 @@ void page_add_file_rmap(struct page *pag
*/
void page_remove_rmap(struct page *page)
{
- BUG_ON(PageReserved(page));
-
if (atomic_add_negative(-1, &page->_mapcount)) {
BUG_ON(page_mapcount(page) < 0);
/*
@@ -643,13 +638,13 @@ static void try_to_unmap_cluster(unsigne
continue;

pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn))
+ if (unlikely(!pfn_valid(pfn))) {
+ invalid_pfn(*pte, vma->vm_flags, address);
continue;
+ }

page = pfn_to_page(pfn);
BUG_ON(PageAnon(page));
- if (PageReserved(page))
- continue;

if (ptep_clear_flush_young(vma, address, pte))
continue;
@@ -812,7 +807,6 @@ int try_to_unmap(struct page *page)
{
int ret;

- BUG_ON(PageReserved(page));
BUG_ON(!PageLocked(page));

if (PageAnon(page))
Index: linux-2.6/drivers/scsi/sg.c
===================================================================
--- linux-2.6.orig/drivers/scsi/sg.c
+++ linux-2.6/drivers/scsi/sg.c
@@ -1887,13 +1887,17 @@ st_unmap_user_pages(struct scatterlist *
int i;

for (i=0; i < nr_pages; i++) {
- if (dirtied && !PageReserved(sgl[i].page))
- SetPageDirty(sgl[i].page);
- /* unlock_page(sgl[i].page); */
+ struct page *page = sgl[i].page;
+
+ /* XXX: just for debug. Remove when PageReserved is removed */
+ BUG_ON(PageReserved(page));
+ if (dirtied)
+ SetPageDirty(page);
+ /* unlock_page(page); */
/* FIXME: cache flush missing for rw==READ
* FIXME: call the correct reference counting function
*/
- page_cache_release(sgl[i].page);
+ page_cache_release(page);
}

return 0;
Index: linux-2.6/drivers/scsi/st.c
===================================================================
--- linux-2.6.orig/drivers/scsi/st.c
+++ linux-2.6/drivers/scsi/st.c
@@ -4435,12 +4435,16 @@ static int sgl_unmap_user_pages(struct s
int i;

for (i=0; i < nr_pages; i++) {
- if (dirtied && !PageReserved(sgl[i].page))
- SetPageDirty(sgl[i].page);
+ struct page *page = sgl[i].page;
+
+ /* XXX: just for debug. Remove when PageReserved is removed */
+ BUG_ON(PageReserved(page));
+ if (dirtied)
+ SetPageDirty(page);
/* FIXME: cache flush missing for rw==READ
* FIXME: call the correct reference counting function
*/
- page_cache_release(sgl[i].page);
+ page_cache_release(page);
}

return 0;
Index: linux-2.6/sound/core/pcm_native.c
===================================================================
--- linux-2.6.orig/sound/core/pcm_native.c
+++ linux-2.6/sound/core/pcm_native.c
@@ -2944,8 +2944,7 @@ static struct page * snd_pcm_mmap_status
return NOPAGE_OOM;
runtime = substream->runtime;
page = virt_to_page(runtime->status);
- if (!PageReserved(page))
- get_page(page);
+ get_page(page);
if (type)
*type = VM_FAULT_MINOR;
return page;
@@ -2987,8 +2986,7 @@ static struct page * snd_pcm_mmap_contro
return NOPAGE_OOM;
runtime = substream->runtime;
page = virt_to_page(runtime->control);
- if (!PageReserved(page))
- get_page(page);
+ get_page(page);
if (type)
*type = VM_FAULT_MINOR;
return page;
@@ -3061,8 +3059,7 @@ static struct page *snd_pcm_mmap_data_no
vaddr = runtime->dma_area + offset;
page = virt_to_page(vaddr);
}
- if (!PageReserved(page))
- get_page(page);
+ get_page(page);
if (type)
*type = VM_FAULT_MINOR;
return page;
Index: linux-2.6/mm/mmap.c
===================================================================
--- linux-2.6.orig/mm/mmap.c
+++ linux-2.6/mm/mmap.c
@@ -1073,6 +1073,17 @@ munmap_back:
error = file->f_op->mmap(file, vma);
if (error)
goto unmap_and_free_vma;
+ if ((vma->vm_flags & (VM_SHARED | VM_WRITE | VM_RESERVED))
+ == (VM_WRITE | VM_RESERVED)) {
+ printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
+ "PROT_WRITE mmap of VM_RESERVED memory, which "
+ "is deprecated. Please report this to "
+ "linux-kernel@xxxxxxxxxxxxxxx\n",current->comm);
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+ error = -EACCES;
+ goto unmap_and_free_vma;
+ }
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
Index: linux-2.6/mm/mprotect.c
===================================================================
--- linux-2.6.orig/mm/mprotect.c
+++ linux-2.6/mm/mprotect.c
@@ -131,6 +131,14 @@ mprotect_fixup(struct vm_area_struct *vm
return -ENOMEM;
newflags |= VM_ACCOUNT;
}
+ if (oldflags & VM_RESERVED) {
+ BUG_ON(oldflags & VM_WRITE);
+ printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
+ "PROT_WRITE mprotect of VM_RESERVED memory, "
+ "which is deprecated. Please report this to "
+ "linux-kernel@xxxxxxxxxxxxxxx\n",current->comm);
+ return -EACCES;
+ }
}

newprot = protection_map[newflags & 0xf];
Index: linux-2.6/mm/bootmem.c
===================================================================
--- linux-2.6.orig/mm/bootmem.c
+++ linux-2.6/mm/bootmem.c
@@ -297,6 +297,7 @@ static unsigned long __init free_all_boo
if (j + 16 < BITS_PER_LONG)
prefetchw(page + j + 16);
__ClearPageReserved(page + j);
+ set_page_count(page + j, 0);
}
__free_pages(page, order);
i += BITS_PER_LONG;
Index: linux-2.6/mm/mempolicy.c
===================================================================
--- linux-2.6.orig/mm/mempolicy.c
+++ linux-2.6/mm/mempolicy.c
@@ -253,8 +253,10 @@ static int check_pte_range(struct mm_str
if (!pte_present(*pte))
continue;
pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn))
+ if (unlikely(!pfn_valid(pfn))) {
+ invalid_pfn(*pte, -1UL, addr);
continue;
+ }
nid = pfn_to_nid(pfn);
if (!test_bit(nid, nodes))
break;
@@ -326,6 +328,8 @@ check_range(struct mm_struct *mm, unsign
first = find_vma(mm, start);
if (!first)
return ERR_PTR(-EFAULT);
+ if (first->vm_flags & VM_RESERVED)
+ return ERR_PTR(-EACCES);
prev = NULL;
for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
if (!vma->vm_next && vma->vm_end < end)
Index: linux-2.6/arch/ppc64/kernel/vdso.c
===================================================================
--- linux-2.6.orig/arch/ppc64/kernel/vdso.c
+++ linux-2.6/arch/ppc64/kernel/vdso.c
@@ -176,13 +176,13 @@ static struct page * vdso_vma_nopage(str
return NOPAGE_SIGBUS;

/*
- * Last page is systemcfg, special handling here, no get_page() a
- * this is a reserved page
+ * Last page is systemcfg.
*/
if ((vma->vm_end - address) <= PAGE_SIZE)
- return virt_to_page(systemcfg);
+ pg = virt_to_page(systemcfg);
+ else
+ pg = virt_to_page(vbase + offset);

- pg = virt_to_page(vbase + offset);
get_page(pg);
DBG(" ->page count: %d\n", page_count(pg));

@@ -600,6 +600,8 @@ void __init vdso_init(void)
ClearPageReserved(pg);
get_page(pg);
}
+
+ get_page(virt_to_page(systemcfg));
}

int in_gate_area_no_task(unsigned long addr)
Index: linux-2.6/kernel/power/swsusp.c
===================================================================
--- linux-2.6.orig/kernel/power/swsusp.c
+++ linux-2.6/kernel/power/swsusp.c
@@ -434,15 +434,23 @@ static int save_highmem_zone(struct zone
continue;
page = pfn_to_page(pfn);
/*
- * This condition results from rvmalloc() sans vmalloc_32()
- * and architectural memory reservations. This should be
- * corrected eventually when the cases giving rise to this
- * are better understood.
+ * PageReserved results from rvmalloc() sans vmalloc_32()
+ * and architectural memory reservations.
+ *
+ * rvmalloc should not cause this, because all implementations
+ * appear to always be using vmalloc_32 on architectures with
+ * highmem. This is a good thing, because we would like to save
+ * rvmalloc pages.
+ *
+ * It appears to be triggered by pages which do not point to
+ * valid memory (see arch/i386/mm/init.c:one_highpage_init(),
+ * which sets PageReserved if the page does not point to valid
+ * RAM.
+ *
+ * XXX: must remove usage of PageReserved!
*/
- if (PageReserved(page)) {
- printk("highmem reserved page?!\n");
+ if (PageReserved(page))
continue;
- }
BUG_ON(PageNosave(page));
if (PageNosaveFree(page))
continue;
@@ -528,10 +536,9 @@ static int saveable(struct zone * zone,
return 0;

page = pfn_to_page(pfn);
- BUG_ON(PageReserved(page) && PageNosave(page));
if (PageNosave(page))
return 0;
- if (PageReserved(page) && pfn_is_nosave(pfn)) {
+ if (pfn_is_nosave(pfn)) {
pr_debug("[nosave pfn 0x%lx]", pfn);
return 0;
}
Index: linux-2.6/mm/shmem.c
===================================================================
--- linux-2.6.orig/mm/shmem.c
+++ linux-2.6/mm/shmem.c
@@ -1523,7 +1523,8 @@ static void do_shmem_file_read(struct fi
index += offset >> PAGE_CACHE_SHIFT;
offset &= ~PAGE_CACHE_MASK;

- page_cache_release(page);
+ if (page != ZERO_PAGE(0))
+ page_cache_release(page);
if (ret != nr || !desc->count)
break;