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-rw-r--r--mm/mremap.c241
1 files changed, 156 insertions, 85 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index 97bff254771..845190898d5 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -261,6 +261,137 @@ static unsigned long move_vma(struct vm_area_struct *vma,
return new_addr;
}
+static struct vm_area_struct *vma_to_resize(unsigned long addr,
+ unsigned long old_len, unsigned long new_len, unsigned long *p)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma = find_vma(mm, addr);
+
+ if (!vma || vma->vm_start > addr)
+ goto Efault;
+
+ if (is_vm_hugetlb_page(vma))
+ goto Einval;
+
+ /* We can't remap across vm area boundaries */
+ if (old_len > vma->vm_end - addr)
+ goto Efault;
+
+ if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) {
+ if (new_len > old_len)
+ goto Efault;
+ }
+
+ if (vma->vm_flags & VM_LOCKED) {
+ unsigned long locked, lock_limit;
+ locked = mm->locked_vm << PAGE_SHIFT;
+ lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+ locked += new_len - old_len;
+ if (locked > lock_limit && !capable(CAP_IPC_LOCK))
+ goto Eagain;
+ }
+
+ if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT))
+ goto Enomem;
+
+ if (vma->vm_flags & VM_ACCOUNT) {
+ unsigned long charged = (new_len - old_len) >> PAGE_SHIFT;
+ if (security_vm_enough_memory(charged))
+ goto Efault;
+ *p = charged;
+ }
+
+ return vma;
+
+Efault: /* very odd choice for most of the cases, but... */
+ return ERR_PTR(-EFAULT);
+Einval:
+ return ERR_PTR(-EINVAL);
+Enomem:
+ return ERR_PTR(-ENOMEM);
+Eagain:
+ return ERR_PTR(-EAGAIN);
+}
+
+static unsigned long mremap_to(unsigned long addr,
+ unsigned long old_len, unsigned long new_addr,
+ unsigned long new_len)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long ret = -EINVAL;
+ unsigned long charged = 0;
+ unsigned long map_flags;
+
+ if (new_addr & ~PAGE_MASK)
+ goto out;
+
+ if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
+ goto out;
+
+ /* Check if the location we're moving into overlaps the
+ * old location at all, and fail if it does.
+ */
+ if ((new_addr <= addr) && (new_addr+new_len) > addr)
+ goto out;
+
+ if ((addr <= new_addr) && (addr+old_len) > new_addr)
+ goto out;
+
+ ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
+ if (ret)
+ goto out;
+
+ ret = do_munmap(mm, new_addr, new_len);
+ if (ret)
+ goto out;
+
+ if (old_len >= new_len) {
+ ret = do_munmap(mm, addr+new_len, old_len - new_len);
+ if (ret && old_len != new_len)
+ goto out;
+ old_len = new_len;
+ }
+
+ vma = vma_to_resize(addr, old_len, new_len, &charged);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto out;
+ }
+
+ map_flags = MAP_FIXED;
+ if (vma->vm_flags & VM_MAYSHARE)
+ map_flags |= MAP_SHARED;
+
+ ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
+ ((addr - vma->vm_start) >> PAGE_SHIFT),
+ map_flags);
+ if (ret & ~PAGE_MASK)
+ goto out1;
+
+ ret = move_vma(vma, addr, old_len, new_len, new_addr);
+ if (!(ret & ~PAGE_MASK))
+ goto out;
+out1:
+ vm_unacct_memory(charged);
+
+out:
+ return ret;
+}
+
+static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
+{
+ unsigned long end = vma->vm_end + delta;
+ if (end < vma->vm_end) /* overflow */
+ return 0;
+ if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
+ return 0;
+ if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
+ 0, MAP_FIXED) & ~PAGE_MASK)
+ return 0;
+ return 1;
+}
+
/*
* Expand (or shrink) an existing mapping, potentially moving it at the
* same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
@@ -294,32 +425,10 @@ unsigned long do_mremap(unsigned long addr,
if (!new_len)
goto out;
- /* new_addr is only valid if MREMAP_FIXED is specified */
if (flags & MREMAP_FIXED) {
- if (new_addr & ~PAGE_MASK)
- goto out;
- if (!(flags & MREMAP_MAYMOVE))
- goto out;
-
- if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
- goto out;
-
- /* Check if the location we're moving into overlaps the
- * old location at all, and fail if it does.
- */
- if ((new_addr <= addr) && (new_addr+new_len) > addr)
- goto out;
-
- if ((addr <= new_addr) && (addr+old_len) > new_addr)
- goto out;
-
- ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
- if (ret)
- goto out;
-
- ret = do_munmap(mm, new_addr, new_len);
- if (ret)
- goto out;
+ if (flags & MREMAP_MAYMOVE)
+ ret = mremap_to(addr, old_len, new_addr, new_len);
+ goto out;
}
/*
@@ -332,60 +441,23 @@ unsigned long do_mremap(unsigned long addr,
if (ret && old_len != new_len)
goto out;
ret = addr;
- if (!(flags & MREMAP_FIXED) || (new_addr == addr))
- goto out;
- old_len = new_len;
+ goto out;
}
/*
- * Ok, we need to grow.. or relocate.
+ * Ok, we need to grow..
*/
- ret = -EFAULT;
- vma = find_vma(mm, addr);
- if (!vma || vma->vm_start > addr)
- goto out;
- if (is_vm_hugetlb_page(vma)) {
- ret = -EINVAL;
- goto out;
- }
- /* We can't remap across vm area boundaries */
- if (old_len > vma->vm_end - addr)
- goto out;
- if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) {
- if (new_len > old_len)
- goto out;
- }
- if (vma->vm_flags & VM_LOCKED) {
- unsigned long locked, lock_limit;
- locked = mm->locked_vm << PAGE_SHIFT;
- lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
- locked += new_len - old_len;
- ret = -EAGAIN;
- if (locked > lock_limit && !capable(CAP_IPC_LOCK))
- goto out;
- }
- if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT)) {
- ret = -ENOMEM;
+ vma = vma_to_resize(addr, old_len, new_len, &charged);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
goto out;
}
- if (vma->vm_flags & VM_ACCOUNT) {
- charged = (new_len - old_len) >> PAGE_SHIFT;
- if (security_vm_enough_memory(charged))
- goto out_nc;
- }
-
/* old_len exactly to the end of the area..
- * And we're not relocating the area.
*/
- if (old_len == vma->vm_end - addr &&
- !((flags & MREMAP_FIXED) && (addr != new_addr)) &&
- (old_len != new_len || !(flags & MREMAP_MAYMOVE))) {
- unsigned long max_addr = TASK_SIZE;
- if (vma->vm_next)
- max_addr = vma->vm_next->vm_start;
+ if (old_len == vma->vm_end - addr) {
/* can we just expand the current mapping? */
- if (max_addr - addr >= new_len) {
+ if (vma_expandable(vma, new_len - old_len)) {
int pages = (new_len - old_len) >> PAGE_SHIFT;
vma_adjust(vma, vma->vm_start,
@@ -409,28 +481,27 @@ unsigned long do_mremap(unsigned long addr,
*/
ret = -ENOMEM;
if (flags & MREMAP_MAYMOVE) {
- if (!(flags & MREMAP_FIXED)) {
- unsigned long map_flags = 0;
- if (vma->vm_flags & VM_MAYSHARE)
- map_flags |= MAP_SHARED;
-
- new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
- vma->vm_pgoff, map_flags);
- if (new_addr & ~PAGE_MASK) {
- ret = new_addr;
- goto out;
- }
-
- ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
- if (ret)
- goto out;
+ unsigned long map_flags = 0;
+ if (vma->vm_flags & VM_MAYSHARE)
+ map_flags |= MAP_SHARED;
+
+ new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
+ vma->vm_pgoff +
+ ((addr - vma->vm_start) >> PAGE_SHIFT),
+ map_flags);
+ if (new_addr & ~PAGE_MASK) {
+ ret = new_addr;
+ goto out;
}
+
+ ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
+ if (ret)
+ goto out;
ret = move_vma(vma, addr, old_len, new_len, new_addr);
}
out:
if (ret & ~PAGE_MASK)
vm_unacct_memory(charged);
-out_nc:
return ret;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-19 02:41:51 +0000