{
struct page *page = pmd_page(*pmd);
pmd_clear(pmd);
+ pte_lock_deinit(page);
pte_free_tlb(tlb, page);
dec_page_state(nr_page_table_pages);
tlb->mm->nr_ptes--;
struct vm_area_struct *next = vma->vm_next;
unsigned long addr = vma->vm_start;
+ /*
+ * Hide vma from rmap and vmtruncate before freeing pgtables
+ */
+ anon_vma_unlink(vma);
+ unlink_file_vma(vma);
+
if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
floor, next? next->vm_start: ceiling);
HPAGE_SIZE)) {
vma = next;
next = vma->vm_next;
+ anon_vma_unlink(vma);
+ unlink_file_vma(vma);
}
free_pgd_range(tlb, addr, vma->vm_end,
floor, next? next->vm_start: ceiling);
int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
{
- struct page *new;
-
- spin_unlock(&mm->page_table_lock);
- new = pte_alloc_one(mm, address);
- spin_lock(&mm->page_table_lock);
+ struct page *new = pte_alloc_one(mm, address);
if (!new)
return -ENOMEM;
- if (pmd_present(*pmd)) /* Another has populated it */
+ pte_lock_init(new);
+ spin_lock(&mm->page_table_lock);
+ if (pmd_present(*pmd)) { /* Another has populated it */
+ pte_lock_deinit(new);
pte_free(new);
- else {
+ } else {
mm->nr_ptes++;
inc_page_state(nr_page_table_pages);
pmd_populate(mm, pmd, new);
}
+ spin_unlock(&mm->page_table_lock);
return 0;
}
/*
* This function is called to print an error when a pte in a
- * !VM_RESERVED region is found pointing to an invalid pfn (which
+ * !VM_UNPAGED region is found pointing to an invalid pfn (which
* is an error.
*
* The calling function must still handle the error.
* 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.
- *
- * dst->page_table_lock is held on entry and exit,
- * but may be dropped within p[mg]d_alloc() and pte_alloc_map().
*/
static inline void
/* make sure dst_mm is on swapoff's mmlist. */
if (unlikely(list_empty(&dst_mm->mmlist))) {
spin_lock(&mmlist_lock);
- list_add(&dst_mm->mmlist, &src_mm->mmlist);
+ if (list_empty(&dst_mm->mmlist))
+ list_add(&dst_mm->mmlist,
+ &src_mm->mmlist);
spin_unlock(&mmlist_lock);
}
}
goto out_set_pte;
}
- /* If the region is VM_RESERVED, the mapping is not
+ /* If the region is VM_UNPAGED, the mapping is not
* mapped via rmap - duplicate the pte as is.
*/
- if (vm_flags & VM_RESERVED)
+ if (vm_flags & VM_UNPAGED)
goto out_set_pte;
pfn = pte_pfn(pte);
/* If the pte points outside of valid memory but
- * the region is not VM_RESERVED, we have a problem.
+ * the region is not VM_UNPAGED, we have a problem.
*/
if (unlikely(!pfn_valid(pfn))) {
print_bad_pte(vma, pte, addr);
unsigned long addr, unsigned long end)
{
pte_t *src_pte, *dst_pte;
+ spinlock_t *src_ptl, *dst_ptl;
int progress = 0;
int rss[2];
again:
rss[1] = rss[0] = 0;
- dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr);
+ dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
if (!dst_pte)
return -ENOMEM;
src_pte = pte_offset_map_nested(src_pmd, addr);
+ src_ptl = pte_lockptr(src_mm, src_pmd);
+ spin_lock(src_ptl);
- spin_lock(&src_mm->page_table_lock);
do {
/*
* We are holding two locks at this point - either of them
if (progress >= 32) {
progress = 0;
if (need_resched() ||
- need_lockbreak(&src_mm->page_table_lock) ||
- need_lockbreak(&dst_mm->page_table_lock))
+ need_lockbreak(src_ptl) ||
+ need_lockbreak(dst_ptl))
break;
}
if (pte_none(*src_pte)) {
copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
progress += 8;
} while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
- spin_unlock(&src_mm->page_table_lock);
+ spin_unlock(src_ptl);
pte_unmap_nested(src_pte - 1);
- pte_unmap(dst_pte - 1);
add_mm_rss(dst_mm, rss[0], rss[1]);
- cond_resched_lock(&dst_mm->page_table_lock);
+ pte_unmap_unlock(dst_pte - 1, dst_ptl);
+ cond_resched();
if (addr != end)
goto again;
return 0;
* readonly mappings. The tradeoff is that copy_page_range is more
* efficient than faulting.
*/
- if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) {
+ if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_UNPAGED))) {
if (!vma->anon_vma)
return 0;
}
return 0;
}
-static void zap_pte_range(struct mmu_gather *tlb,
+static unsigned long 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)
+ long *zap_work, struct zap_details *details)
{
struct mm_struct *mm = tlb->mm;
pte_t *pte;
+ spinlock_t *ptl;
int file_rss = 0;
int anon_rss = 0;
- pte = pte_offset_map(pmd, addr);
+ pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
do {
pte_t ptent = *pte;
- if (pte_none(ptent))
+ if (pte_none(ptent)) {
+ (*zap_work)--;
continue;
+ }
if (pte_present(ptent)) {
struct page *page = NULL;
- if (!(vma->vm_flags & VM_RESERVED)) {
+
+ (*zap_work) -= PAGE_SIZE;
+
+ if (!(vma->vm_flags & VM_UNPAGED)) {
unsigned long pfn = pte_pfn(ptent);
if (unlikely(!pfn_valid(pfn)))
print_bad_pte(vma, ptent, addr);
if (!pte_file(ptent))
free_swap_and_cache(pte_to_swp_entry(ptent));
pte_clear_full(mm, addr, pte, tlb->fullmm);
- } while (pte++, addr += PAGE_SIZE, addr != end);
+ } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
add_mm_rss(mm, file_rss, anon_rss);
- pte_unmap(pte - 1);
+ pte_unmap_unlock(pte - 1, ptl);
+
+ return addr;
}
-static inline void zap_pmd_range(struct mmu_gather *tlb,
+static inline unsigned long 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)
+ long *zap_work, struct zap_details *details)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
- if (pmd_none_or_clear_bad(pmd))
+ if (pmd_none_or_clear_bad(pmd)) {
+ (*zap_work)--;
continue;
- zap_pte_range(tlb, vma, pmd, addr, next, details);
- } while (pmd++, addr = next, addr != end);
+ }
+ next = zap_pte_range(tlb, vma, pmd, addr, next,
+ zap_work, details);
+ } while (pmd++, addr = next, (addr != end && *zap_work > 0));
+
+ return addr;
}
-static inline void zap_pud_range(struct mmu_gather *tlb,
+static inline unsigned long 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)
+ long *zap_work, struct zap_details *details)
{
pud_t *pud;
unsigned long next;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
- if (pud_none_or_clear_bad(pud))
+ if (pud_none_or_clear_bad(pud)) {
+ (*zap_work)--;
continue;
- zap_pmd_range(tlb, vma, pud, addr, next, details);
- } while (pud++, addr = next, addr != end);
+ }
+ next = zap_pmd_range(tlb, vma, pud, addr, next,
+ zap_work, details);
+ } while (pud++, addr = next, (addr != end && *zap_work > 0));
+
+ return addr;
}
-static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
+static unsigned long unmap_page_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma,
unsigned long addr, unsigned long end,
- struct zap_details *details)
+ long *zap_work, struct zap_details *details)
{
pgd_t *pgd;
unsigned long next;
pgd = pgd_offset(vma->vm_mm, addr);
do {
next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd))
+ if (pgd_none_or_clear_bad(pgd)) {
+ (*zap_work)--;
continue;
- zap_pud_range(tlb, vma, pgd, addr, next, details);
- } while (pgd++, addr = next, addr != end);
+ }
+ next = zap_pud_range(tlb, vma, pgd, addr, next,
+ zap_work, details);
+ } while (pgd++, addr = next, (addr != end && *zap_work > 0));
tlb_end_vma(tlb, vma);
+
+ return addr;
}
#ifdef CONFIG_PREEMPT
/**
* unmap_vmas - unmap a range of memory covered by a list of vma's
* @tlbp: address of the caller's struct mmu_gather
- * @mm: the controlling mm_struct
* @vma: the starting vma
* @start_addr: virtual address at which to start unmapping
* @end_addr: virtual address at which to end unmapping
*
* Returns the end address of the unmapping (restart addr if interrupted).
*
- * Unmap all pages in the vma list. Called under page_table_lock.
+ * Unmap all pages in the vma list.
*
- * We aim to not hold page_table_lock for too long (for scheduling latency
- * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
+ * We aim to not hold locks for too long (for scheduling latency reasons).
+ * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
* return the ending mmu_gather to the caller.
*
* Only addresses between `start' and `end' will be unmapped.
* ensure that any thus-far unmapped pages are flushed before unmap_vmas()
* drops the lock and schedules.
*/
-unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
+unsigned long unmap_vmas(struct mmu_gather **tlbp,
struct vm_area_struct *vma, unsigned long start_addr,
unsigned long end_addr, unsigned long *nr_accounted,
struct zap_details *details)
{
- unsigned long zap_bytes = ZAP_BLOCK_SIZE;
+ long zap_work = ZAP_BLOCK_SIZE;
unsigned long tlb_start = 0; /* For tlb_finish_mmu */
int tlb_start_valid = 0;
unsigned long start = start_addr;
*nr_accounted += (end - start) >> PAGE_SHIFT;
while (start != end) {
- unsigned long block;
-
if (!tlb_start_valid) {
tlb_start = start;
tlb_start_valid = 1;
}
- if (is_vm_hugetlb_page(vma)) {
- block = end - start;
+ if (unlikely(is_vm_hugetlb_page(vma))) {
unmap_hugepage_range(vma, start, end);
- } else {
- block = min(zap_bytes, end - start);
- unmap_page_range(*tlbp, vma, start,
- start + block, details);
+ zap_work -= (end - start) /
+ (HPAGE_SIZE / PAGE_SIZE);
+ start = end;
+ } else
+ start = unmap_page_range(*tlbp, vma,
+ start, end, &zap_work, details);
+
+ if (zap_work > 0) {
+ BUG_ON(start != end);
+ break;
}
- start += block;
- zap_bytes -= block;
- if ((long)zap_bytes > 0)
- continue;
-
tlb_finish_mmu(*tlbp, tlb_start, start);
if (need_resched() ||
- need_lockbreak(&mm->page_table_lock) ||
(i_mmap_lock && need_lockbreak(i_mmap_lock))) {
if (i_mmap_lock) {
- /* must reset count of rss freed */
- *tlbp = tlb_gather_mmu(mm, fullmm);
+ *tlbp = NULL;
goto out;
}
- spin_unlock(&mm->page_table_lock);
cond_resched();
- spin_lock(&mm->page_table_lock);
}
- *tlbp = tlb_gather_mmu(mm, fullmm);
+ *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
tlb_start_valid = 0;
- zap_bytes = ZAP_BLOCK_SIZE;
+ zap_work = ZAP_BLOCK_SIZE;
}
}
out:
unsigned long end = address + size;
unsigned long nr_accounted = 0;
- if (is_vm_hugetlb_page(vma)) {
- zap_hugepage_range(vma, address, size);
- return end;
- }
-
lru_add_drain();
- spin_lock(&mm->page_table_lock);
tlb = tlb_gather_mmu(mm, 0);
update_hiwater_rss(mm);
- end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
- tlb_finish_mmu(tlb, address, end);
- spin_unlock(&mm->page_table_lock);
+ end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
+ if (tlb)
+ tlb_finish_mmu(tlb, address, end);
return end;
}
/*
* Do a quick page-table lookup for a single page.
- * mm->page_table_lock must be held.
*/
-static struct page *__follow_page(struct mm_struct *mm, unsigned long address,
- int read, int write, int accessed)
+struct page *follow_page(struct mm_struct *mm, unsigned long address,
+ unsigned int flags)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *ptep, pte;
+ spinlock_t *ptl;
unsigned long pfn;
struct page *page;
- page = follow_huge_addr(mm, address, write);
- if (! IS_ERR(page))
- return page;
+ page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
+ if (!IS_ERR(page)) {
+ BUG_ON(flags & FOLL_GET);
+ goto out;
+ }
+ page = NULL;
pgd = pgd_offset(mm, address);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- goto out;
+ goto no_page_table;
pud = pud_offset(pgd, address);
if (pud_none(*pud) || unlikely(pud_bad(*pud)))
- goto out;
+ goto no_page_table;
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+ goto no_page_table;
+
+ if (pmd_huge(*pmd)) {
+ BUG_ON(flags & FOLL_GET);
+ page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
goto out;
- if (pmd_huge(*pmd))
- return follow_huge_pmd(mm, address, pmd, write);
+ }
- ptep = pte_offset_map(pmd, address);
+ ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
if (!ptep)
goto out;
pte = *ptep;
- pte_unmap(ptep);
- if (pte_present(pte)) {
- if (write && !pte_write(pte))
- goto out;
- if (read && !pte_read(pte))
- goto out;
- pfn = pte_pfn(pte);
- if (pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- if (accessed) {
- if (write && !pte_dirty(pte) &&!PageDirty(page))
- set_page_dirty(page);
- mark_page_accessed(page);
- }
- return page;
- }
- }
+ if (!pte_present(pte))
+ goto unlock;
+ if ((flags & FOLL_WRITE) && !pte_write(pte))
+ goto unlock;
+ pfn = pte_pfn(pte);
+ if (!pfn_valid(pfn))
+ goto unlock;
+ page = pfn_to_page(pfn);
+ if (flags & FOLL_GET)
+ get_page(page);
+ if (flags & FOLL_TOUCH) {
+ if ((flags & FOLL_WRITE) &&
+ !pte_dirty(pte) && !PageDirty(page))
+ set_page_dirty(page);
+ mark_page_accessed(page);
+ }
+unlock:
+ pte_unmap_unlock(ptep, ptl);
out:
- return NULL;
-}
-
-inline struct page *
-follow_page(struct mm_struct *mm, unsigned long address, int write)
-{
- return __follow_page(mm, address, 0, write, 1);
-}
-
-/*
- * check_user_page_readable() can be called frm niterrupt context by oprofile,
- * so we need to avoid taking any non-irq-safe locks
- */
-int check_user_page_readable(struct mm_struct *mm, unsigned long address)
-{
- return __follow_page(mm, address, 1, 0, 0) != NULL;
-}
-EXPORT_SYMBOL(check_user_page_readable);
-
-static inline int
-untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
- unsigned long address)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
-
- /* Check if the vma is for an anonymous mapping. */
- if (vma->vm_ops && vma->vm_ops->nopage)
- return 0;
-
- /* Check if page directory entry exists. */
- pgd = pgd_offset(mm, address);
- if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- return 1;
-
- pud = pud_offset(pgd, address);
- if (pud_none(*pud) || unlikely(pud_bad(*pud)))
- return 1;
-
- /* Check if page middle directory entry exists. */
- pmd = pmd_offset(pud, address);
- if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
- return 1;
+ return page;
- /* There is a pte slot for 'address' in 'mm'. */
- return 0;
+no_page_table:
+ /*
+ * When core dumping an enormous anonymous area that nobody
+ * has touched so far, we don't want to allocate page tables.
+ */
+ if (flags & FOLL_ANON) {
+ page = ZERO_PAGE(address);
+ if (flags & FOLL_GET)
+ get_page(page);
+ BUG_ON(flags & FOLL_WRITE);
+ }
+ return page;
}
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
struct page **pages, struct vm_area_struct **vmas)
{
int i;
- unsigned int flags;
+ unsigned int vm_flags;
/*
* Require read or write permissions.
* If 'force' is set, we only require the "MAY" flags.
*/
- flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+ vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+ vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
i = 0;
do {
- struct vm_area_struct * vma;
+ struct vm_area_struct *vma;
+ unsigned int foll_flags;
vma = find_extend_vma(mm, start);
if (!vma && in_gate_area(tsk, start)) {
continue;
}
- if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
- || !(flags & vma->vm_flags))
+ if (!vma || (vma->vm_flags & VM_IO)
+ || !(vm_flags & vma->vm_flags))
return i ? : -EFAULT;
if (is_vm_hugetlb_page(vma)) {
&start, &len, i);
continue;
}
- spin_lock(&mm->page_table_lock);
+
+ foll_flags = FOLL_TOUCH;
+ if (pages)
+ foll_flags |= FOLL_GET;
+ if (!write && !(vma->vm_flags & VM_LOCKED) &&
+ (!vma->vm_ops || !vma->vm_ops->nopage))
+ foll_flags |= FOLL_ANON;
+
do {
- int write_access = write;
struct page *page;
- cond_resched_lock(&mm->page_table_lock);
- while (!(page = follow_page(mm, start, write_access))) {
- int ret;
-
- /*
- * Shortcut for anonymous pages. We don't want
- * to force the creation of pages tables for
- * insanely big anonymously mapped areas that
- * nobody touched so far. This is important
- * for doing a core dump for these mappings.
- */
- if (!write && untouched_anonymous_page(mm,vma,start)) {
- page = ZERO_PAGE(start);
- break;
- }
- spin_unlock(&mm->page_table_lock);
- ret = __handle_mm_fault(mm, vma, start, write_access);
+ if (write)
+ foll_flags |= FOLL_WRITE;
+ cond_resched();
+ while (!(page = follow_page(mm, start, foll_flags))) {
+ int ret;
+ ret = __handle_mm_fault(mm, vma, start,
+ foll_flags & FOLL_WRITE);
/*
* The VM_FAULT_WRITE bit tells us that do_wp_page has
* broken COW when necessary, even if maybe_mkwrite
* subsequent page lookups as if they were reads.
*/
if (ret & VM_FAULT_WRITE)
- write_access = 0;
+ foll_flags &= ~FOLL_WRITE;
switch (ret & ~VM_FAULT_WRITE) {
case VM_FAULT_MINOR:
default:
BUG();
}
- spin_lock(&mm->page_table_lock);
}
if (pages) {
pages[i] = page;
flush_dcache_page(page);
- page_cache_get(page);
}
if (vmas)
vmas[i] = vma;
start += PAGE_SIZE;
len--;
} while (len && start < vma->vm_end);
- spin_unlock(&mm->page_table_lock);
} while (len);
return i;
}
unsigned long addr, unsigned long end, pgprot_t prot)
{
pte_t *pte;
+ spinlock_t *ptl;
- pte = pte_alloc_map(mm, pmd, addr);
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
do {
BUG_ON(!pte_none(*pte));
set_pte_at(mm, addr, pte, zero_pte);
} while (pte++, addr += PAGE_SIZE, addr != end);
- pte_unmap(pte - 1);
+ pte_unmap_unlock(pte - 1, ptl);
return 0;
}
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
flush_cache_range(vma, addr, end);
- spin_lock(&mm->page_table_lock);
do {
next = pgd_addr_end(addr, end);
err = zeromap_pud_range(mm, pgd, addr, next, prot);
if (err)
break;
} while (pgd++, addr = next, addr != end);
- spin_unlock(&mm->page_table_lock);
return err;
}
unsigned long pfn, pgprot_t prot)
{
pte_t *pte;
+ spinlock_t *ptl;
- pte = pte_alloc_map(mm, pmd, addr);
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
do {
set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
- pte_unmap(pte - 1);
+ pte_unmap_unlock(pte - 1, ptl);
return 0;
}
* rest of the world about it:
* VM_IO tells people not to look at these pages
* (accesses can have side effects).
- * VM_RESERVED tells the core MM not to "manage" these pages
- * (e.g. refcount, mapcount, try to swap them out).
+ * VM_RESERVED is specified all over the place, because
+ * in 2.4 it kept swapout's vma scan off this vma; but
+ * in 2.6 the LRU scan won't even find its pages, so this
+ * flag means no more than count its pages in reserved_vm,
+ * and omit it from core dump, even when VM_IO turned off.
+ * VM_UNPAGED tells the core MM not to "manage" these pages
+ * (e.g. refcount, mapcount, try to swap them out): in
+ * particular, zap_pte_range does not try to free them.
*/
- vma->vm_flags |= VM_IO | VM_RESERVED;
+ vma->vm_flags |= VM_IO | VM_RESERVED | VM_UNPAGED;
BUG_ON(addr >= end);
pfn -= addr >> PAGE_SHIFT;
pgd = pgd_offset(mm, addr);
flush_cache_range(vma, addr, end);
- spin_lock(&mm->page_table_lock);
do {
next = pgd_addr_end(addr, end);
err = remap_pud_range(mm, pgd, addr, next,
if (err)
break;
} while (pgd++, addr = next, addr != end);
- spin_unlock(&mm->page_table_lock);
return err;
}
EXPORT_SYMBOL(remap_pfn_range);
/*
+ * handle_pte_fault chooses page fault handler according to an entry
+ * which was read non-atomically. Before making any commitment, on
+ * those architectures or configurations (e.g. i386 with PAE) which
+ * might give a mix of unmatched parts, do_swap_page and do_file_page
+ * must check under lock before unmapping the pte and proceeding
+ * (but do_wp_page is only called after already making such a check;
+ * and do_anonymous_page and do_no_page can safely check later on).
+ */
+static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
+ pte_t *page_table, pte_t orig_pte)
+{
+ int same = 1;
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
+ if (sizeof(pte_t) > sizeof(unsigned long)) {
+ spinlock_t *ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ same = pte_same(*page_table, orig_pte);
+ spin_unlock(ptl);
+ }
+#endif
+ pte_unmap(page_table);
+ return same;
+}
+
+/*
* Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
* servicing faults for write access. In the normal case, do always want
* pte_mkwrite. But get_user_pages can cause write faults for mappings
* change only once the write actually happens. This avoids a few races,
* and potentially makes it more efficient.
*
- * We hold the mm semaphore and the page_table_lock on entry and exit
- * with the page_table_lock released.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), with pte both mapped and locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- pte_t orig_pte)
+ spinlock_t *ptl, pte_t orig_pte)
{
struct page *old_page, *new_page;
unsigned long pfn = pte_pfn(orig_pte);
pte_t entry;
int ret = VM_FAULT_MINOR;
- BUG_ON(vma->vm_flags & VM_RESERVED);
+ BUG_ON(vma->vm_flags & VM_UNPAGED);
if (unlikely(!pfn_valid(pfn))) {
/*
* Ok, we need to copy. Oh, well..
*/
page_cache_get(old_page);
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
if (unlikely(anon_vma_prepare(vma)))
goto oom;
/*
* Re-check the pte - we dropped the lock
*/
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (likely(pte_same(*page_table, orig_pte))) {
page_remove_rmap(old_page);
if (!PageAnon(old_page)) {
ptep_establish(vma, address, page_table, entry);
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
-
lru_cache_add_active(new_page);
page_add_anon_rmap(new_page, vma, address);
page_cache_release(new_page);
page_cache_release(old_page);
unlock:
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
return ret;
oom:
page_cache_release(old_page);
restart_addr = zap_page_range(vma, start_addr,
end_addr - start_addr, details);
-
- /*
- * We cannot rely on the break test in unmap_vmas:
- * on the one hand, we don't want to restart our loop
- * just because that broke out for the page_table_lock;
- * on the other hand, it does no test when vma is small.
- */
need_break = need_resched() ||
need_lockbreak(details->i_mmap_lock);
}
/*
- * We hold the mm semaphore and the page_table_lock on entry and
- * should release the pagetable lock on exit..
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
int write_access, pte_t orig_pte)
{
+ spinlock_t *ptl;
struct page *page;
swp_entry_t entry;
pte_t pte;
int ret = VM_FAULT_MINOR;
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+ goto out;
entry = pte_to_swp_entry(orig_pte);
page = lookup_swap_cache(entry);
page = read_swap_cache_async(entry, vma, address);
if (!page) {
/*
- * Back out if somebody else faulted in this pte while
- * we released the page table lock.
+ * Back out if somebody else faulted in this pte
+ * while we released the pte lock.
*/
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (likely(pte_same(*page_table, orig_pte)))
ret = VM_FAULT_OOM;
goto unlock;
lock_page(page);
/*
- * Back out if somebody else faulted in this pte while we
- * released the page table lock.
+ * Back out if somebody else already faulted in this pte.
*/
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (unlikely(!pte_same(*page_table, orig_pte)))
goto out_nomap;
if (write_access) {
if (do_wp_page(mm, vma, address,
- page_table, pmd, pte) == VM_FAULT_OOM)
+ page_table, pmd, ptl, pte) == VM_FAULT_OOM)
ret = VM_FAULT_OOM;
goto out;
}
update_mmu_cache(vma, address, pte);
lazy_mmu_prot_update(pte);
unlock:
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
out:
return ret;
out_nomap:
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
unlock_page(page);
page_cache_release(page);
return ret;
}
/*
- * We are called with the MM semaphore and page_table_lock
- * spinlock held to protect against concurrent faults in
- * multithreaded programs.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
int write_access)
{
- struct page *page = ZERO_PAGE(addr);
+ struct page *page;
+ spinlock_t *ptl;
pte_t entry;
- /* Mapping of ZERO_PAGE - vm_page_prot is readonly */
- entry = mk_pte(page, vma->vm_page_prot);
-
if (write_access) {
/* Allocate our own private page. */
pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
if (unlikely(anon_vma_prepare(vma)))
goto oom;
if (!page)
goto oom;
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
-
- if (!pte_none(*page_table)) {
- page_cache_release(page);
- goto unlock;
- }
- inc_mm_counter(mm, anon_rss);
entry = mk_pte(page, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (!pte_none(*page_table))
+ goto release;
+ inc_mm_counter(mm, anon_rss);
lru_cache_add_active(page);
SetPageReferenced(page);
page_add_anon_rmap(page, vma, address);
} else {
+ /* Map the ZERO_PAGE - vm_page_prot is readonly */
+ page = ZERO_PAGE(address);
+ page_cache_get(page);
+ entry = mk_pte(page, vma->vm_page_prot);
+
+ ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ if (!pte_none(*page_table))
+ goto release;
inc_mm_counter(mm, file_rss);
page_add_file_rmap(page);
- page_cache_get(page);
}
set_pte_at(mm, address, page_table, entry);
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
unlock:
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
return VM_FAULT_MINOR;
+release:
+ page_cache_release(page);
+ goto unlock;
oom:
return VM_FAULT_OOM;
}
* 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.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
int write_access)
{
+ spinlock_t *ptl;
struct page *new_page;
struct address_space *mapping = NULL;
pte_t entry;
int anon = 0;
pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
anon = 1;
}
- spin_lock(&mm->page_table_lock);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
/*
* For a file-backed vma, someone could have truncated or otherwise
* invalidated this page. If unmap_mapping_range got called,
* retry getting the page.
*/
if (mapping && unlikely(sequence != mapping->truncate_count)) {
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
page_cache_release(new_page);
cond_resched();
sequence = mapping->truncate_count;
smp_rmb();
goto retry;
}
- page_table = pte_offset_map(pmd, address);
/*
* This silly early PAGE_DIRTY setting removes a race
inc_mm_counter(mm, anon_rss);
lru_cache_add_active(new_page);
page_add_anon_rmap(new_page, vma, address);
- } else if (!(vma->vm_flags & VM_RESERVED)) {
+ } else if (!(vma->vm_flags & VM_UNPAGED)) {
inc_mm_counter(mm, file_rss);
page_add_file_rmap(new_page);
}
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
unlock:
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(page_table, ptl);
return ret;
oom:
page_cache_release(new_page);
* Fault of a previously existing named mapping. Repopulate the pte
* from the encoded file_pte if possible. This enables swappable
* nonlinear vmas.
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
pgoff_t pgoff;
int err;
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+ return VM_FAULT_MINOR;
if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
/*
* with external mmu caches can use to update those (ie the Sparc or
* PowerPC hashed page tables that act as extended TLBs).
*
- * Note the "page_table_lock". It is to protect against kswapd removing
- * pages from under us. Note that kswapd only ever _removes_ pages, never
- * adds them. As such, once we have noticed that the page is not present,
- * we can drop the lock early.
- *
- * The adding of pages is protected by the MM semaphore (which we hold),
- * so we don't need to worry about a page being suddenly been added into
- * our VM.
- *
- * We enter with the pagetable spinlock held, we are supposed to
- * release it when done.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static inline int handle_pte_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
pte_t *pte, pmd_t *pmd, int write_access)
{
pte_t entry;
+ pte_t old_entry;
+ spinlock_t *ptl;
- entry = *pte;
+ old_entry = entry = *pte;
if (!pte_present(entry)) {
if (pte_none(entry)) {
if (!vma->vm_ops || !vma->vm_ops->nopage)
pte, pmd, write_access, entry);
}
+ ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ if (unlikely(!pte_same(*pte, entry)))
+ goto unlock;
if (write_access) {
if (!pte_write(entry))
- return do_wp_page(mm, vma, address, pte, pmd, entry);
+ return do_wp_page(mm, vma, address,
+ pte, pmd, ptl, entry);
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- ptep_set_access_flags(vma, address, pte, entry, write_access);
- update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
- pte_unmap(pte);
- spin_unlock(&mm->page_table_lock);
+ if (!pte_same(old_entry, entry)) {
+ ptep_set_access_flags(vma, address, pte, entry, write_access);
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
+ } else {
+ /*
+ * This is needed only for protection faults but the arch code
+ * is not yet telling us if this is a protection fault or not.
+ * This still avoids useless tlb flushes for .text page faults
+ * with threads.
+ */
+ if (write_access)
+ flush_tlb_page(vma, address);
+ }
+unlock:
+ pte_unmap_unlock(pte, ptl);
return VM_FAULT_MINOR;
}
if (unlikely(is_vm_hugetlb_page(vma)))
return hugetlb_fault(mm, vma, address, write_access);
- /*
- * We need the page table lock to synchronize with kswapd
- * and the SMP-safe atomic PTE updates.
- */
pgd = pgd_offset(mm, address);
- spin_lock(&mm->page_table_lock);
-
pud = pud_alloc(mm, pgd, address);
if (!pud)
- goto oom;
-
+ return VM_FAULT_OOM;
pmd = pmd_alloc(mm, pud, address);
if (!pmd)
- goto oom;
-
+ return VM_FAULT_OOM;
pte = pte_alloc_map(mm, pmd, address);
if (!pte)
- goto oom;
-
- return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
+ return VM_FAULT_OOM;
- oom:
- spin_unlock(&mm->page_table_lock);
- return VM_FAULT_OOM;
+ return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
}
#ifndef __PAGETABLE_PUD_FOLDED
*/
int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
{
- pud_t *new;
-
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
- new = pud_alloc_one(mm, address);
- if (!new) {
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_lock(&mm->page_table_lock);
+ pud_t *new = pud_alloc_one(mm, address);
+ if (!new)
return -ENOMEM;
- }
spin_lock(&mm->page_table_lock);
if (pgd_present(*pgd)) /* Another has populated it */
pud_free(new);
else
pgd_populate(mm, pgd, new);
- if (mm == &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&mm->page_table_lock);
return 0;
}
#endif /* __PAGETABLE_PUD_FOLDED */
*/
int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
{
- pmd_t *new;
-
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
- new = pmd_alloc_one(mm, address);
- if (!new) {
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_lock(&mm->page_table_lock);
+ pmd_t *new = pmd_alloc_one(mm, address);
+ if (!new)
return -ENOMEM;
- }
spin_lock(&mm->page_table_lock);
#ifndef __ARCH_HAS_4LEVEL_HACK
else
pgd_populate(mm, pud, new);
#endif /* __ARCH_HAS_4LEVEL_HACK */
- if (mm == &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&mm->page_table_lock);
return 0;
}
#endif /* __PAGETABLE_PMD_FOLDED */
gate_vma.vm_start = FIXADDR_USER_START;
gate_vma.vm_end = FIXADDR_USER_END;
gate_vma.vm_page_prot = PAGE_READONLY;
- gate_vma.vm_flags = VM_RESERVED;
+ gate_vma.vm_flags = 0;
return 0;
}
__initcall(gate_vma_init);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff