int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, struct page *page, pgprot_t prot)
{
+ struct inode *inode;
+ pgoff_t size;
int err = -ENOMEM;
pte_t *pte;
pgd_t *pgd;
pmd_t *pmd;
pte_t pte_val;
- /*
- * We use page_add_file_rmap below: if install_page is
- * ever extended to anonymous pages, this will warn us.
- */
- BUG_ON(!page_mapping(page));
-
pgd = pgd_offset(mm, addr);
spin_lock(&mm->page_table_lock);
if (!pte)
goto err_unlock;
+ /*
+ * This page may have been truncated. Tell the
+ * caller about it.
+ */
+ 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);
// mm->rss++;
unsigned long end = start + size;
struct vm_area_struct *vma;
int err = -EINVAL;
+ int has_write_lock = 0;
if (__prot)
return err;
#endif
/* We need down_write() to change vma->vm_flags. */
- down_write(&mm->mmap_sem);
+ down_read(&mm->mmap_sem);
+ retry:
vma = find_vma(mm, start);
/*
* or VM_LOCKED, but VM_LOCKED could be revoked later on).
*/
if (vma && (vma->vm_flags & VM_SHARED) &&
- (!vma->vm_private_data || (vma->vm_flags & VM_RESERVED)) &&
+ (!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) {
/* 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_prio_tree_init(vma);
- list_add_tail(&vma->shared.vm_set.list,
- &mapping->i_mmap_nonlinear);
+ vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
flush_dcache_mmap_unlock(mapping);
spin_unlock(&mapping->i_mmap_lock);
}
- /* ->populate can take a long time, so downgrade the lock. */
- downgrade_write(&mm->mmap_sem);
err = vma->vm_ops->populate(vma, start, size,
vma->vm_page_prot,
pgoff, flags & MAP_NONBLOCK);
* it after ->populate completes, and that would prevent
* downgrading the lock. (Locks can't be upgraded).
*/
+ }
+ if (likely(!has_write_lock))
up_read(&mm->mmap_sem);
- } else {
+ else
up_write(&mm->mmap_sem);
- }
return err;
}