*
* started by Ingo Molnar, Copyright (C) 2002, 2003
*/
-
+#include <linux/backing-dev.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/file.h>
#include <linux/rmap.h>
#include <linux/module.h>
#include <linux/syscalls.h>
+#include <linux/mmu_notifier.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
-static inline void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
+#include "internal.h"
+
+static void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
pte_t pte = *ptep;
- if (pte_none(pte))
- return;
if (pte_present(pte)) {
- unsigned long pfn = pte_pfn(pte);
+ struct page *page;
- flush_cache_page(vma, addr, pfn);
+ flush_cache_page(vma, addr, pte_pfn(pte));
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);
- }
+ page = vm_normal_page(vma, addr, pte);
+ if (page) {
+ if (pte_dirty(pte))
+ set_page_dirty(page);
+ page_remove_rmap(page);
+ page_cache_release(page);
+ update_hiwater_rss(mm);
+ dec_mm_counter(mm, file_rss);
}
} else {
if (!pte_file(pte))
free_swap_and_cache(pte_to_swp_entry(pte));
- pte_clear(mm, addr, ptep);
+ pte_clear_not_present_full(mm, addr, ptep, 0);
}
}
/*
- * Install a file page to a given virtual memory address, release any
+ * Install a file pte to a given virtual memory address, release any
* previously existing mapping.
*/
-int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, struct page *page, pgprot_t prot)
+static int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long pgoff, pgprot_t prot)
{
- struct inode *inode;
- pgoff_t size;
int err = -ENOMEM;
pte_t *pte;
- pmd_t *pmd;
- pud_t *pud;
- pgd_t *pgd;
- pte_t pte_val;
-
- pgd = pgd_offset(mm, addr);
- spin_lock(&mm->page_table_lock);
-
- pud = pud_alloc(mm, pgd, addr);
- if (!pud)
- goto err_unlock;
+ spinlock_t *ptl;
- pmd = pmd_alloc(mm, pud, addr);
- if (!pmd)
- goto err_unlock;
-
- pte = pte_alloc_map(mm, pmd, addr);
+ pte = get_locked_pte(mm, addr, &ptl);
if (!pte)
- goto err_unlock;
+ goto out;
+
+ if (!pte_none(*pte))
+ zap_pte(mm, vma, addr, pte);
+ set_pte_at(mm, addr, pte, pgoff_to_pte(pgoff));
/*
- * This page may have been truncated. Tell the
- * caller about it.
+ * We don't need to run update_mmu_cache() here because the "file pte"
+ * being installed by install_file_pte() is not a real pte - it's a
+ * non-present entry (like a swap entry), noting what file offset should
+ * be mapped there when there's a fault (in a non-linear vma where
+ * that's not obvious).
*/
- err = -EINVAL;
- inode = vma->vm_file->f_mapping->host;
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (!page->mapping || page->index >= size)
- goto err_unlock;
-
- zap_pte(mm, vma, addr, pte);
-
- inc_mm_counter(mm,rss);
- flush_icache_page(vma, page);
- set_pte_at(mm, addr, pte, mk_pte(page, prot));
- page_add_file_rmap(page);
- pte_val = *pte;
- pte_unmap(pte);
- update_mmu_cache(vma, addr, pte_val);
-
+ pte_unmap_unlock(pte, ptl);
err = 0;
-err_unlock:
- spin_unlock(&mm->page_table_lock);
+out:
return err;
}
-EXPORT_SYMBOL(install_page);
-
-/*
- * Install a file pte to a given virtual memory address, release any
- * previously existing mapping.
- */
-int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, unsigned long pgoff, pgprot_t prot)
+static int populate_range(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long size, pgoff_t pgoff)
{
- int err = -ENOMEM;
- pte_t *pte;
- pmd_t *pmd;
- pud_t *pud;
- pgd_t *pgd;
- pte_t pte_val;
-
- pgd = pgd_offset(mm, addr);
- spin_lock(&mm->page_table_lock);
-
- pud = pud_alloc(mm, pgd, addr);
- if (!pud)
- goto err_unlock;
+ int err;
- pmd = pmd_alloc(mm, pud, addr);
- if (!pmd)
- goto err_unlock;
-
- pte = pte_alloc_map(mm, pmd, addr);
- if (!pte)
- goto err_unlock;
+ do {
+ err = install_file_pte(mm, vma, addr, pgoff, vma->vm_page_prot);
+ if (err)
+ return err;
- zap_pte(mm, vma, addr, pte);
+ size -= PAGE_SIZE;
+ addr += PAGE_SIZE;
+ pgoff++;
+ } while (size);
- set_pte_at(mm, addr, pte, pgoff_to_pte(pgoff));
- pte_val = *pte;
- pte_unmap(pte);
- update_mmu_cache(vma, addr, pte_val);
- spin_unlock(&mm->page_table_lock);
- return 0;
+ return 0;
-err_unlock:
- spin_unlock(&mm->page_table_lock);
- return err;
}
-
-/***
- * sys_remap_file_pages - remap arbitrary pages of a shared backing store
- * file within an existing vma.
+/**
+ * sys_remap_file_pages - remap arbitrary pages of an existing VM_SHARED vma
* @start: start of the remapped virtual memory range
* @size: size of the remapped virtual memory range
- * @prot: new protection bits of the range
- * @pgoff: to be mapped page of the backing store file
+ * @prot: new protection bits of the range (see NOTE)
+ * @pgoff: to-be-mapped page of the backing store file
* @flags: 0 or MAP_NONBLOCKED - the later will cause no IO.
*
- * this syscall works purely via pagetables, so it's the most efficient
+ * sys_remap_file_pages remaps arbitrary pages of an existing VM_SHARED vma
+ * (shared backing store file).
+ *
+ * This syscall works purely via pagetables, so it's the most efficient
* way to map the same (large) file into a given virtual window. Unlike
* mmap()/mremap() it does not create any new vmas. The new mappings are
* also safe across swapout.
*
- * NOTE: the 'prot' parameter right now is ignored, and the vma's default
- * protection is used. Arbitrary protections might be implemented in the
- * future.
+ * NOTE: the @prot parameter right now is ignored (but must be zero),
+ * and the vma's default protection is used. Arbitrary protections
+ * might be implemented in the future.
*/
-asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
- unsigned long __prot, unsigned long pgoff, unsigned long flags)
+SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
+ unsigned long, prot, unsigned long, pgoff, unsigned long, flags)
{
struct mm_struct *mm = current->mm;
struct address_space *mapping;
int err = -EINVAL;
int has_write_lock = 0;
- if (__prot)
+ if (prot)
return err;
/*
* Sanitize the syscall parameters:
* Make sure the vma is shared, that it supports prefaulting,
* and that the remapped range is valid and fully within
* the single existing vma. vm_private_data is used as a
- * swapout cursor in a VM_NONLINEAR vma (unless VM_RESERVED
- * or VM_LOCKED, but VM_LOCKED could be revoked later on).
+ * swapout cursor in a VM_NONLINEAR vma.
*/
- if (vma && (vma->vm_flags & VM_SHARED) &&
- (!vma->vm_private_data ||
- (vma->vm_flags & (VM_NONLINEAR|VM_RESERVED))) &&
- vma->vm_ops && vma->vm_ops->populate &&
- end > start && start >= vma->vm_start &&
- end <= vma->vm_end) {
+ if (!vma || !(vma->vm_flags & VM_SHARED))
+ goto out;
- /* Must set VM_NONLINEAR before any pages are populated. */
- if (pgoff != linear_page_index(vma, start) &&
- !(vma->vm_flags & VM_NONLINEAR)) {
- if (!has_write_lock) {
- up_read(&mm->mmap_sem);
- down_write(&mm->mmap_sem);
- has_write_lock = 1;
- goto retry;
- }
- mapping = vma->vm_file->f_mapping;
- spin_lock(&mapping->i_mmap_lock);
- flush_dcache_mmap_lock(mapping);
- vma->vm_flags |= VM_NONLINEAR;
- vma_prio_tree_remove(vma, &mapping->i_mmap);
- vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
- flush_dcache_mmap_unlock(mapping);
- spin_unlock(&mapping->i_mmap_lock);
+ if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
+ goto out;
+
+ if (!(vma->vm_flags & VM_CAN_NONLINEAR))
+ goto out;
+
+ if (end <= start || start < vma->vm_start || end > vma->vm_end)
+ goto out;
+
+ /* Must set VM_NONLINEAR before any pages are populated. */
+ if (!(vma->vm_flags & VM_NONLINEAR)) {
+ /* Don't need a nonlinear mapping, exit success */
+ if (pgoff == linear_page_index(vma, start)) {
+ err = 0;
+ goto out;
}
- err = vma->vm_ops->populate(vma, start, size,
- vma->vm_page_prot,
- pgoff, flags & MAP_NONBLOCK);
+ if (!has_write_lock) {
+ up_read(&mm->mmap_sem);
+ down_write(&mm->mmap_sem);
+ has_write_lock = 1;
+ goto retry;
+ }
+ mapping = vma->vm_file->f_mapping;
+ /*
+ * page_mkclean doesn't work on nonlinear vmas, so if
+ * dirty pages need to be accounted, emulate with linear
+ * vmas.
+ */
+ if (mapping_cap_account_dirty(mapping)) {
+ unsigned long addr;
+ struct file *file = vma->vm_file;
+
+ flags &= MAP_NONBLOCK;
+ get_file(file);
+ addr = mmap_region(file, start, size,
+ flags, vma->vm_flags, pgoff);
+ fput(file);
+ if (IS_ERR_VALUE(addr)) {
+ err = addr;
+ } else {
+ BUG_ON(addr != start);
+ err = 0;
+ }
+ goto out;
+ }
+ spin_lock(&mapping->i_mmap_lock);
+ flush_dcache_mmap_lock(mapping);
+ vma->vm_flags |= VM_NONLINEAR;
+ vma_prio_tree_remove(vma, &mapping->i_mmap);
+ vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
+ flush_dcache_mmap_unlock(mapping);
+ spin_unlock(&mapping->i_mmap_lock);
+ }
+ if (vma->vm_flags & VM_LOCKED) {
/*
- * We can't clear VM_NONLINEAR because we'd have to do
- * it after ->populate completes, and that would prevent
- * downgrading the lock. (Locks can't be upgraded).
+ * drop PG_Mlocked flag for over-mapped range
*/
+ unsigned int saved_flags = vma->vm_flags;
+ munlock_vma_pages_range(vma, start, start + size);
+ vma->vm_flags = saved_flags;
+ }
+
+ mmu_notifier_invalidate_range_start(mm, start, start + size);
+ err = populate_range(mm, vma, start, size, pgoff);
+ mmu_notifier_invalidate_range_end(mm, start, start + size);
+ if (!err && !(flags & MAP_NONBLOCK)) {
+ if (vma->vm_flags & VM_LOCKED) {
+ /*
+ * might be mapping previously unmapped range of file
+ */
+ mlock_vma_pages_range(vma, start, start + size);
+ } else {
+ if (unlikely(has_write_lock)) {
+ downgrade_write(&mm->mmap_sem);
+ has_write_lock = 0;
+ }
+ make_pages_present(start, start+size);
+ }
}
+
+ /*
+ * We can't clear VM_NONLINEAR because we'd have to do
+ * it after ->populate completes, and that would prevent
+ * downgrading the lock. (Locks can't be upgraded).
+ */
+
+out:
if (likely(!has_write_lock))
up_read(&mm->mmap_sem);
else
return err;
}
-
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff