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

mm/mremap.c

+12 −4
Original line number Diff line number Diff line
@@ -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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