[PATCH v3 07/10] iov_iter: Add extract kunit tests for ITER_UBUF and ITER_IOVEC

David Howells
2023-09-22T11:31:17Z

Add extraction kunit tests for ITER_UBUF- and ITER_IOVEC-type iterators.
This attaches a userspace VM with a mapped file in it temporarily to the
test thread.

[!] Note that this requires the kernel thread running the test to obtain
and deploy an mm_struct so that a user-side buffer can be created with mmap
- basically it has to emulated part of execve(). Doing so requires access
to additional core symbols: mm_alloc(), vm_area_alloc(), insert_vm_struct()
and arch_pick_mmap_layout(). See the iov_kunit_create_user_buf() function
added in the patch.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: Christoph Hellwig <hch@lst.de>
cc: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: Brendan Higgins <brendanhiggins@google.com>
cc: David Gow <davidgow@google.com>
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-kselftest@vger.kernel.org
cc: kunit-dev@googlegroups.com
---
lib/kunit_iov_iter.c | 164 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 164 insertions(+)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c
index 34f0d82674ee..fdf598e49c0b 100644
--- a/lib/kunit_iov_iter.c
+++ b/lib/kunit_iov_iter.c
@@ -863,6 +863,168 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test)
KUNIT_SUCCEED();
}

+/*
+ * Test the extraction of ITER_UBUF-type iterators.
+ */
+static void __init iov_kunit_extract_pages_ubuf(struct kunit *test)
+{
+ const struct iov_kunit_range *pr;
+ struct iov_iter iter;
+ struct page **bpages, *pagelist[8], **pages = pagelist;
+ ssize_t len;
+ size_t bufsize, size = 0, npages;
+ int i, from;
+ u8 __user *buffer;
+
+ bufsize = 0x100000;
+ npages = bufsize / PAGE_SIZE;
+
+ buffer = iov_kunit_create_user_buf(test, npages, &bpages);
+
+ for (pr = kvec_test_ranges; pr->page >= 0; pr++) {
+ from = pr->from;
+ size = pr->to - from;
+ KUNIT_ASSERT_LE(test, pr->to, bufsize);
+
+ iov_iter_ubuf(&iter, ITER_SOURCE, buffer + pr->from, size);
+
+ do {
+ size_t offset0 = LONG_MAX;
+
+ for (i = 0; i < ARRAY_SIZE(pagelist); i++)
+ pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a;
+
+ len = iov_iter_extract_pages(&iter, &pages, 100 * 1024,
+ ARRAY_SIZE(pagelist), 0, &offset0);
+ KUNIT_EXPECT_GE(test, len, 0);
+ if (len < 0)
+ break;
+ KUNIT_EXPECT_LE(test, len, size);
+ KUNIT_EXPECT_EQ(test, iter.count, size - len);
+ if (len == 0)
+ break;
+ size -= len;
+ KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0);
+ KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE);
+
+ /* We're only checking the page pointers */
+ unpin_user_pages(pages, (offset0 + len) / PAGE_SIZE);
+
+ for (i = 0; i < ARRAY_SIZE(pagelist); i++) {
+ struct page *p;
+ ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0);
+ int ix;
+
+ KUNIT_ASSERT_GE(test, part, 0);
+ ix = from / PAGE_SIZE;
+ KUNIT_ASSERT_LT(test, ix, npages);
+ p = bpages[ix];
+ KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p);
+ KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE);
+ from += part;
+ len -= part;
+ KUNIT_ASSERT_GE(test, len, 0);
+ if (len == 0)
+ break;
+ offset0 = 0;
+ }
+
+ if (test->status == KUNIT_FAILURE)
+ goto stop;
+ } while (iov_iter_count(&iter) > 0);
+
+ KUNIT_EXPECT_EQ(test, size, 0);
+ KUNIT_EXPECT_EQ(test, iter.count, 0);
+ KUNIT_EXPECT_EQ(test, iter.iov_offset, pr->to - pr->from);
+ }
+
+stop:
+ KUNIT_SUCCEED();
+}
+
+/*
+ * Test the extraction of ITER_IOVEC-type iterators.
+ */
+static void __init iov_kunit_extract_pages_iovec(struct kunit *test)
+{
+ const struct iov_kunit_range *pr;
+ struct iov_iter iter;
+ struct iovec iov[8];
+ struct page **bpages, *pagelist[8], **pages = pagelist;
+ ssize_t len;
+ size_t bufsize, size = 0, npages;
+ int i, from;
+ u8 __user *buffer;
+
+ bufsize = 0x100000;
+ npages = bufsize / PAGE_SIZE;
+
+ buffer = iov_kunit_create_user_buf(test, npages, &bpages);
+
+ iov_kunit_load_iovec(test, &iter, ITER_SOURCE, iov, ARRAY_SIZE(iov),
+ buffer, bufsize, kvec_test_ranges);
+ size = iter.count;
+
+ pr = kvec_test_ranges;
+ from = pr->from;
+ do {
+ size_t offset0 = LONG_MAX;
+
+ for (i = 0; i < ARRAY_SIZE(pagelist); i++)
+ pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a;
+
+ len = iov_iter_extract_pages(&iter, &pages, 100 * 1024,
+ ARRAY_SIZE(pagelist), 0, &offset0);
+ KUNIT_EXPECT_GE(test, len, 0);
+ if (len < 0)
+ break;
+ KUNIT_EXPECT_LE(test, len, size);
+ KUNIT_EXPECT_EQ(test, iter.count, size - len);
+ if (len == 0)
+ break;
+ size -= len;
+ KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0);
+ KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE);
+
+ /* We're only checking the page pointers */
+ unpin_user_pages(pages, (offset0 + len) / PAGE_SIZE);
+
+ for (i = 0; i < ARRAY_SIZE(pagelist); i++) {
+ struct page *p;
+ ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0);
+ int ix;
+
+ KUNIT_ASSERT_GE(test, part, 0);
+ while (from == pr->to) {
+ pr++;
+ from = pr->from;
+ if (pr->page < 0)
+ goto stop;
+ }
+
+ ix = from / PAGE_SIZE;
+ KUNIT_ASSERT_LT(test, ix, npages);
+ p = bpages[ix];
+ KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p);
+ KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE);
+ from += part;
+ len -= part;
+ KUNIT_ASSERT_GE(test, len, 0);
+ if (len == 0)
+ break;
+ offset0 = 0;
+ }
+
+ if (test->status == KUNIT_FAILURE)
+ break;
+ } while (iov_iter_count(&iter) > 0);
+
+stop:
+ KUNIT_EXPECT_EQ(test, size, 0);
+ KUNIT_EXPECT_EQ(test, iter.count, 0);
+ KUNIT_SUCCEED();
+}
+
/*
* Test the extraction of ITER_KVEC-type iterators.
*/
@@ -1111,6 +1273,8 @@ static struct kunit_case __refdata iov_kunit_cases[] = {
KUNIT_CASE(iov_kunit_copy_from_bvec),
KUNIT_CASE(iov_kunit_copy_to_xarray),
KUNIT_CASE(iov_kunit_copy_from_xarray),
+ KUNIT_CASE(iov_kunit_extract_pages_ubuf),
+ KUNIT_CASE(iov_kunit_extract_pages_iovec),
KUNIT_CASE(iov_kunit_extract_pages_kvec),
KUNIT_CASE(iov_kunit_extract_pages_bvec),
KUNIT_CASE(iov_kunit_extract_pages_xarray),