tools: testing: add expand-only mode VMA test

Add a test to assert that VMG_FLAG_JUST_EXPAND functions as expected - that
is, when the VMA iterator is positioned at the previous VMA and no VMAs
proceed it, we observe an expansion with all state as expected.

Explicitly place a prior VMA that would otherwise fail this test if the
mode were not enabled (as it would traverse to the previous-previous VMA).

Link: https://lkml.kernel.org/r/d2f88330254a6448092412bf7dfe077a579ab0dc.1729174352.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
index c53f220eb6cc039ac884ca063dc16d85cf57d9ca..b33b47342d4182457ad26391b6844cdacd284250 100644 (file)
--- a/tools/testing/vma/vma.c
+++ b/tools/testing/vma/vma.c
@@ -1522,6 +1522,45 @@ static bool test_copy_vma(void)
        return true;
 }
 
+static bool test_expand_only_mode(void)
+{
+       unsigned long flags = VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE;
+       struct mm_struct mm = {};
+       VMA_ITERATOR(vmi, &mm, 0);
+       struct vm_area_struct *vma_prev, *vma;
+       VMG_STATE(vmg, &mm, &vmi, 0x5000, 0x9000, flags, 5);
+
+       /*
+        * Place a VMA prior to the one we're expanding so we assert that we do
+        * not erroneously try to traverse to the previous VMA even though we
+        * have, through the use of VMG_FLAG_JUST_EXPAND, indicated we do not
+        * need to do so.
+        */
+       alloc_and_link_vma(&mm, 0, 0x2000, 0, flags);
+
+       /*
+        * We will be positioned at the prev VMA, but looking to expand to
+        * 0x9000.
+        */
+       vma_iter_set(&vmi, 0x3000);
+       vma_prev = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags);
+       vmg.prev = vma_prev;
+       vmg.merge_flags = VMG_FLAG_JUST_EXPAND;
+
+       vma = vma_merge_new_range(&vmg);
+       ASSERT_NE(vma, NULL);
+       ASSERT_EQ(vma, vma_prev);
+       ASSERT_EQ(vmg.state, VMA_MERGE_SUCCESS);
+       ASSERT_EQ(vma->vm_start, 0x3000);
+       ASSERT_EQ(vma->vm_end, 0x9000);
+       ASSERT_EQ(vma->vm_pgoff, 3);
+       ASSERT_TRUE(vma_write_started(vma));
+       ASSERT_EQ(vma_iter_addr(&vmi), 0x3000);
+
+       cleanup_mm(&mm, &vmi);
+       return true;
+}
+
 int main(void)
 {
        int num_tests = 0, num_fail = 0;
@@ -1553,6 +1592,7 @@ int main(void)
        TEST(vmi_prealloc_fail);
        TEST(merge_extend);
        TEST(copy_vma);
+       TEST(expand_only_mode);
 
 #undef TEST