mm: remap_file_pages() fixes

[linux-2.6-block.git] / mm / fremap.c

diff --git a/mm/fremap.c b/mm/fremap.c
index a0aaf0e56800394be8b9ae0d0da47712b6e0bb53..2db886e310445f25b8b4abee9217a88e44bffde9 100644 (file)
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -160,15 +160,11 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
        /*
         * 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.
+        * the single existing vma.
         */
        if (!vma || !(vma->vm_flags & VM_SHARED))
                goto out;
 
-       if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
-               goto out;
-
        if (!vma->vm_ops || !vma->vm_ops->remap_pages)
                goto out;
 
@@ -177,6 +173,13 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 
        /* Must set VM_NONLINEAR before any pages are populated. */
        if (!(vma->vm_flags & VM_NONLINEAR)) {
+               /*
+                * vm_private_data is used as a swapout cursor
+                * in a VM_NONLINEAR vma.
+                */
+               if (vma->vm_private_data)
+                       goto out;
+
                /* Don't need a nonlinear mapping, exit success */
                if (pgoff == linear_page_index(vma, start)) {
                        err = 0;
@@ -184,6 +187,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
                }
 
                if (!has_write_lock) {
+get_write_lock:
                        up_read(&mm->mmap_sem);
                        down_write(&mm->mmap_sem);
                        has_write_lock = 1;
@@ -199,7 +203,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
                        unsigned long addr;
                        struct file *file = get_file(vma->vm_file);
 
-                       flags &= MAP_NONBLOCK;
+                       flags = (flags & MAP_NONBLOCK) | MAP_POPULATE;
                        addr = mmap_region(file, start, size,
                                        flags, vma->vm_flags, pgoff);
                        fput(file);
@@ -225,6 +229,8 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
                 * drop PG_Mlocked flag for over-mapped range
                 */
                vm_flags_t saved_flags = vma->vm_flags;
+               if (!has_write_lock)
+                       goto get_write_lock;
                munlock_vma_pages_range(vma, start, start + size);
                vma->vm_flags = saved_flags;
        }
@@ -232,13 +238,13 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
        mmu_notifier_invalidate_range_start(mm, start, start + size);
        err = vma->vm_ops->remap_pages(vma, start, size, pgoff);
        mmu_notifier_invalidate_range_end(mm, start, start + size);
-       if (!err && !(flags & MAP_NONBLOCK)) {
+       if (!err) {
                if (vma->vm_flags & VM_LOCKED) {
                        /*
                         * might be mapping previously unmapped range of file
                         */
                        mlock_vma_pages_range(vma, start, start + size);
-               } else {
+               } else if (!(flags & MAP_NONBLOCK)) {
                        if (unlikely(has_write_lock)) {
                                downgrade_write(&mm->mmap_sem);
                                has_write_lock = 0;