mm/vma: move unmapped_area() internals to mm/vma.c

We want to be able to unit test the unmapped area logic, so move it to
mm/vma.c.  The wrappers which invoke this remain in place in mm/mmap.c.

In addition, naturally, update the existing test code to enable this to be
compiled in userland.

Link: https://lkml.kernel.org/r/53a57a52a64ea54e9d129d2e2abca3a538022379.1733248985.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 0 insertions, 109 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index 775db706b822..7aa372a75326 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -580,115 +580,6 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
 }
 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
 
-/**
- * unmapped_area() - Find an area between the low_limit and the high_limit with
- * the correct alignment and offset, all from @info. Note: current->mm is used
- * for the search.
- *
- * @info: The unmapped area information including the range [low_limit -
- * high_limit), the alignment offset and mask.
- *
- * Return: A memory address or -ENOMEM.
- */
-static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
-{
-	unsigned long length, gap;
-	unsigned long low_limit, high_limit;
-	struct vm_area_struct *tmp;
-	VMA_ITERATOR(vmi, current->mm, 0);
-
-	/* Adjust search length to account for worst case alignment overhead */
-	length = info->length + info->align_mask + info->start_gap;
-	if (length < info->length)
-		return -ENOMEM;
-
-	low_limit = info->low_limit;
-	if (low_limit < mmap_min_addr)
-		low_limit = mmap_min_addr;
-	high_limit = info->high_limit;
-retry:
-	if (vma_iter_area_lowest(&vmi, low_limit, high_limit, length))
-		return -ENOMEM;
-
-	/*
-	 * Adjust for the gap first so it doesn't interfere with the
-	 * later alignment. The first step is the minimum needed to
-	 * fulill the start gap, the next steps is the minimum to align
-	 * that. It is the minimum needed to fulill both.
-	 */
-	gap = vma_iter_addr(&vmi) + info->start_gap;
-	gap += (info->align_offset - gap) & info->align_mask;
-	tmp = vma_next(&vmi);
-	if (tmp && (tmp->vm_flags & VM_STARTGAP_FLAGS)) { /* Avoid prev check if possible */
-		if (vm_start_gap(tmp) < gap + length - 1) {
-			low_limit = tmp->vm_end;
-			vma_iter_reset(&vmi);
-			goto retry;
-		}
-	} else {
-		tmp = vma_prev(&vmi);
-		if (tmp && vm_end_gap(tmp) > gap) {
-			low_limit = vm_end_gap(tmp);
-			vma_iter_reset(&vmi);
-			goto retry;
-		}
-	}
-
-	return gap;
-}
-
-/**
- * unmapped_area_topdown() - Find an area between the low_limit and the
- * high_limit with the correct alignment and offset at the highest available
- * address, all from @info. Note: current->mm is used for the search.
- *
- * @info: The unmapped area information including the range [low_limit -
- * high_limit), the alignment offset and mask.
- *
- * Return: A memory address or -ENOMEM.
- */
-static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
-{
-	unsigned long length, gap, gap_end;
-	unsigned long low_limit, high_limit;
-	struct vm_area_struct *tmp;
-	VMA_ITERATOR(vmi, current->mm, 0);
-
-	/* Adjust search length to account for worst case alignment overhead */
-	length = info->length + info->align_mask + info->start_gap;
-	if (length < info->length)
-		return -ENOMEM;
-
-	low_limit = info->low_limit;
-	if (low_limit < mmap_min_addr)
-		low_limit = mmap_min_addr;
-	high_limit = info->high_limit;
-retry:
-	if (vma_iter_area_highest(&vmi, low_limit, high_limit, length))
-		return -ENOMEM;
-
-	gap = vma_iter_end(&vmi) - info->length;
-	gap -= (gap - info->align_offset) & info->align_mask;
-	gap_end = vma_iter_end(&vmi);
-	tmp = vma_next(&vmi);
-	if (tmp && (tmp->vm_flags & VM_STARTGAP_FLAGS)) { /* Avoid prev check if possible */
-		if (vm_start_gap(tmp) < gap_end) {
-			high_limit = vm_start_gap(tmp);
-			vma_iter_reset(&vmi);
-			goto retry;
-		}
-	} else {
-		tmp = vma_prev(&vmi);
-		if (tmp && vm_end_gap(tmp) > gap) {
-			high_limit = tmp->vm_start;
-			vma_iter_reset(&vmi);
-			goto retry;
-		}
-	}
-
-	return gap;
-}
-
 /*
  * Determine if the allocation needs to ensure that there is no
  * existing mapping within it's guard gaps, for use as start_gap.