[PATCH] ioremap balanced with iounmap for drivers/video/vesafb

[sfrench/cifs-2.6.git] / mm / mremap.c

diff --git a/mm/mremap.c b/mm/mremap.c
index 616facc3d28a87bb463042e085e6a4fa35e72f66..9c769fa29f32aff451ef6ff86ce836c1fc0bf856 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -13,6 +13,7 @@
 #include <linux/shm.h>
 #include <linux/mman.h>
 #include <linux/swap.h>
+#include <linux/capability.h>
 #include <linux/fs.h>
 #include <linux/highmem.h>
 #include <linux/security.h>
@@ -28,9 +29,6 @@ static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
        pud_t *pud;
        pmd_t *pmd;
 
-       /*
-        * We don't need page_table_lock: we have mmap_sem exclusively.
-        */
        pgd = pgd_offset(mm, addr);
        if (pgd_none_or_clear_bad(pgd))
                return NULL;
@@ -50,25 +48,20 @@ static pmd_t *alloc_new_pmd(struct mm_struct *mm, unsigned long addr)
 {
        pgd_t *pgd;
        pud_t *pud;
-       pmd_t *pmd = NULL;
+       pmd_t *pmd;
 
-       /*
-        * We do need page_table_lock: because allocators expect that.
-        */
-       spin_lock(&mm->page_table_lock);
        pgd = pgd_offset(mm, addr);
        pud = pud_alloc(mm, pgd, addr);
        if (!pud)
-               goto out;
+               return NULL;
 
        pmd = pmd_alloc(mm, pud, addr);
        if (!pmd)
-               goto out;
+               return NULL;
 
        if (!pmd_present(*pmd) && __pte_alloc(mm, pmd, addr))
-               pmd = NULL;
-out:
-       spin_unlock(&mm->page_table_lock);
+               return NULL;
+
        return pmd;
 }
 
@@ -80,6 +73,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
        struct address_space *mapping = NULL;
        struct mm_struct *mm = vma->vm_mm;
        pte_t *old_pte, *new_pte, pte;
+       spinlock_t *old_ptl, *new_ptl;
 
        if (vma->vm_file) {
                /*
@@ -95,9 +89,16 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
                        new_vma->vm_truncate_count = 0;
        }
 
-       spin_lock(&mm->page_table_lock);
-       old_pte = pte_offset_map(old_pmd, old_addr);
-       new_pte = pte_offset_map_nested(new_pmd, new_addr);
+       /*
+        * We don't have to worry about the ordering of src and dst
+        * pte locks because exclusive mmap_sem prevents deadlock.
+        */
+       old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
+       new_pte = pte_offset_map_nested(new_pmd, new_addr);
+       new_ptl = pte_lockptr(mm, new_pmd);
+       if (new_ptl != old_ptl)
+               spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
+       arch_enter_lazy_mmu_mode();
 
        for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
                                   new_pte++, new_addr += PAGE_SIZE) {
@@ -109,9 +110,11 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
                set_pte_at(mm, new_addr, new_pte, pte);
        }
 
+       arch_leave_lazy_mmu_mode();
+       if (new_ptl != old_ptl)
+               spin_unlock(new_ptl);
        pte_unmap_nested(new_pte - 1);
-       pte_unmap(old_pte - 1);
-       spin_unlock(&mm->page_table_lock);
+       pte_unmap_unlock(old_pte - 1, old_ptl);
        if (mapping)
                spin_unlock(&mapping->i_mmap_lock);
 }
@@ -323,7 +326,7 @@ unsigned long do_mremap(unsigned long addr,
        /* We can't remap across vm area boundaries */
        if (old_len > vma->vm_end - addr)
                goto out;
-       if (vma->vm_flags & VM_DONTEXPAND) {
+       if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) {
                if (new_len > old_len)
                        goto out;
        }