mlock: mlocked pages are unevictable

[net-next-2.6.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 71cdefd1ef14898ae73270c30edbdf01cb12db49..9fef7272fb9e81324959efeea12e7b74c6ce6262 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -64,6 +64,8 @@
 
 #include "internal.h"
 
+#include "internal.h"
+
 #ifndef CONFIG_NEED_MULTIPLE_NODES
 /* use the per-pgdat data instead for discontigmem - mbligh */
 unsigned long max_mapnr;
@@ -1129,12 +1131,17 @@ static inline int use_zero_page(struct vm_area_struct *vma)
        return !vma->vm_ops || !vma->vm_ops->fault;
 }
 
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-               unsigned long start, int len, int write, int force,
+
+
+int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                    unsigned long start, int len, int flags,
                struct page **pages, struct vm_area_struct **vmas)
 {
        int i;
-       unsigned int vm_flags;
+       unsigned int vm_flags = 0;
+       int write = !!(flags & GUP_FLAGS_WRITE);
+       int force = !!(flags & GUP_FLAGS_FORCE);
+       int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
 
        if (len <= 0)
                return 0;
@@ -1158,7 +1165,9 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                        pud_t *pud;
                        pmd_t *pmd;
                        pte_t *pte;
-                       if (write) /* user gate pages are read-only */
+
+                       /* user gate pages are read-only */
+                       if (!ignore && write)
                                return i ? : -EFAULT;
                        if (pg > TASK_SIZE)
                                pgd = pgd_offset_k(pg);
@@ -1190,8 +1199,9 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                        continue;
                }
 
-               if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
-                               || !(vm_flags & vma->vm_flags))
+               if (!vma ||
+                   (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
+                   (!ignore && !(vm_flags & vma->vm_flags)))
                        return i ? : -EFAULT;
 
                if (is_vm_hugetlb_page(vma)) {
@@ -1266,6 +1276,23 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
        } while (len);
        return i;
 }
+
+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)
+{
+       int flags = 0;
+
+       if (write)
+               flags |= GUP_FLAGS_WRITE;
+       if (force)
+               flags |= GUP_FLAGS_FORCE;
+
+       return __get_user_pages(tsk, mm,
+                               start, len, flags,
+                               pages, vmas);
+}
+
 EXPORT_SYMBOL(get_user_pages);
 
 pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
@@ -1858,6 +1885,15 @@ gotten:
        new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
        if (!new_page)
                goto oom;
+       /*
+        * Don't let another task, with possibly unlocked vma,
+        * keep the mlocked page.
+        */
+       if (vma->vm_flags & VM_LOCKED) {
+               lock_page(old_page);    /* for LRU manipulation */
+               clear_page_mlock(old_page);
+               unlock_page(old_page);
+       }
        cow_user_page(new_page, old_page, address, vma);
        __SetPageUptodate(new_page);
 
@@ -2325,7 +2361,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
        page_add_anon_rmap(page, vma, address);
 
        swap_free(entry);
-       if (vm_swap_full())
+       if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
                remove_exclusive_swap_page(page);
        unlock_page(page);
 
@@ -2465,6 +2501,12 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                                ret = VM_FAULT_OOM;
                                goto out;
                        }
+                       /*
+                        * Don't let another task, with possibly unlocked vma,
+                        * keep the mlocked page.
+                        */
+                       if (vma->vm_flags & VM_LOCKED)
+                               clear_page_mlock(vmf.page);
                        copy_user_highpage(page, vmf.page, address, vma);
                        __SetPageUptodate(page);
                } else {