Commit 1a0ef85f authored by Al Viro's avatar Al Viro
Browse files

do_mremap() untangling, part 3



Take the check for being able to expand vma in place into a separate
helper.
Acked-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ecc1a899
......@@ -366,6 +366,17 @@ out:
return ret;
}
static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
{
unsigned long max_addr = TASK_SIZE;
if (vma->vm_next)
max_addr = vma->vm_next->vm_start;
if (max_addr - vma->vm_end < delta)
return 0;
/* we need to do arch-specific checks here */
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)
......@@ -430,11 +441,8 @@ unsigned long do_mremap(unsigned long addr,
/* old_len exactly to the end of the area..
*/
if (old_len == vma->vm_end - addr) {
unsigned long max_addr = TASK_SIZE;
if (vma->vm_next)
max_addr = vma->vm_next->vm_start;
/* 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,
......
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