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untangling do_mremap(), part 1

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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)

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2009-11-24 07:17:46 -05:00
parent 3ef884b4c0
commit 54f5de7099
1 changed files with 55 additions and 33 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

88
mm/mremap.c
View file

@ -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)
@ -340,39 +392,10 @@ 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)
vma = vma_to_resize(addr, old_len, new_len, &charged);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
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;
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..
@ -430,7 +453,6 @@ unsigned long do_mremap(unsigned long addr,
out:
if (ret & ~PAGE_MASK)
vm_unacct_memory(charged);
out_nc:
return ret;
}