*/
#include <linux/slab.h>
+#include <linux/backing-dev.h>
#include <linux/mm.h>
#include <linux/shm.h>
#include <linux/mman.h>
* Note this is a helper function intended to be used by LSMs which
* wish to use this logic.
*/
-int __vm_enough_memory(long pages, int cap_sys_admin)
+int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
{
unsigned long free, allowed;
/* Don't let a single process grow too big:
leave 3% of the size of this process for other processes */
- allowed -= current->mm->total_vm / 32;
+ allowed -= mm->total_vm / 32;
/*
* cast `allowed' as a signed long because vm_committed_space
return -ENOMEM;
}
-EXPORT_SYMBOL(__vm_enough_memory);
-
/*
* Requires inode->i_mapping->i_mmap_lock
*/
}
EXPORT_SYMBOL(do_mmap_pgoff);
+/*
+ * Some shared mappigns will want the pages marked read-only
+ * to track write events. If so, we'll downgrade vm_page_prot
+ * to the private version (using protection_map[] without the
+ * VM_SHARED bit).
+ */
+int vma_wants_writenotify(struct vm_area_struct *vma)
+{
+ unsigned int vm_flags = vma->vm_flags;
+
+ /* If it was private or non-writable, the write bit is already clear */
+ if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
+ return 0;
+
+ /* The backer wishes to know when pages are first written to? */
+ if (vma->vm_ops && vma->vm_ops->page_mkwrite)
+ return 1;
+
+ /* The open routine did something to the protections already? */
+ if (pgprot_val(vma->vm_page_prot) !=
+ pgprot_val(vm_get_page_prot(vm_flags)))
+ return 0;
+
+ /* Specialty mapping? */
+ if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
+ return 0;
+
+ /* Can the mapping track the dirty pages? */
+ return vma->vm_file && vma->vm_file->f_mapping &&
+ mapping_cap_account_dirty(vma->vm_file->f_mapping);
+}
+
+
unsigned long mmap_region(struct file *file, unsigned long addr,
unsigned long len, unsigned long flags,
unsigned int vm_flags, unsigned long pgoff,
vma->vm_start = addr;
vma->vm_end = addr + len;
vma->vm_flags = vm_flags;
- vma->vm_page_prot = protection_map[vm_flags &
- (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+ vma->vm_page_prot = vm_get_page_prot(vm_flags);
vma->vm_pgoff = pgoff;
if (file) {
vm_flags = vma->vm_flags;
if (vma_wants_writenotify(vma))
- vma->vm_page_prot =
- protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)];
+ vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
vma->vm_end = addr + len;
vma->vm_pgoff = pgoff;
vma->vm_flags = flags;
- vma->vm_page_prot = protection_map[flags &
- (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+ vma->vm_page_prot = vm_get_page_prot(flags);
vma_link(mm, vma, prev, rb_link, rb_parent);
out:
mm->total_vm += len >> PAGE_SHIFT;
if (__vma && __vma->vm_start < vma->vm_end)
return -ENOMEM;
if ((vma->vm_flags & VM_ACCOUNT) &&
- security_vm_enough_memory(vma_pages(vma)))
+ security_vm_enough_memory_mm(mm, vma_pages(vma)))
return -ENOMEM;
vma_link(mm, vma, prev, rb_link, rb_parent);
return 0;
vma->vm_end = addr + len;
vma->vm_flags = vm_flags | mm->def_flags;
- vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+ vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
vma->vm_ops = &special_mapping_vmops;
vma->vm_private_data = pages;