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Subject[PATCH 1/19] untangling do_mremap(), part 1
From

Take locating vma and checks on it to a separate helper (it will be
shared between MREMAP_FIXED/non-MREMAP_FIXED cases when we split
them in the next patch)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
mm/mremap.c | 88 +++++++++++++++++++++++++++++++++++++----------------------
1 files changed, 55 insertions(+), 33 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index 97bff25..6776136 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -261,6 +261,58 @@ 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);
+}
+
/*
* Expand (or shrink) an existing mapping, potentially moving it at the
* same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
@@ -340,41 +392,12 @@ unsigned long do_mremap(unsigned long addr,
/*
* Ok, we need to grow.. or relocate.
*/
- 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.
*/
@@ -430,7 +453,6 @@ unsigned long do_mremap(unsigned long addr,
out:
if (ret & ~PAGE_MASK)
vm_unacct_memory(charged);
-out_nc:
return ret;
}

--
1.5.6.5



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