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-rw-r--r--mm/fremap.c22
1 files changed, 14 insertions, 8 deletions
diff --git a/mm/fremap.c b/mm/fremap.c
index a0aaf0e56800..2db886e31044 100644
--- 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;