Re: [PATCH v3 5/5] lib: kunit_iov_iter: Add tests for extract_iter_to_sg

["Christian A. Ehrhardt" <lk@c--e.de>]

Hi David,

On Tue, Apr 21, 2026 at 01:45:33PM +0800, David Gow wrote:
> Le 27/03/2026 à 05:49, Christian A. Ehrhardt a écrit :
> > Add test cases that test extract_iter_to_sg.
> > 
> > For each iterator type an iterator is loaded with a suitable
> > buffer. The iterator is then extracted to a scatterlist with
> > multiple calls to extract_iter_to_sg. The final scatterlist
> > is copied into a scratch buffer.
> > 
> > The test passes if the scratch buffer contains the same data
> > as the original buffer.
> > 
> > The new tests demonstrate bugs in extract_iter_to_sg
> > for kvec and user iterators that are fixed by the previous
> > commits.
> > 
> > Cc: David Howells <dhowells@redhat.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
> > ---
> 
> Hmm... this is failing on powerpc, where PAGE_SIZE is 64k:
> 
> [13:20:40] # iov_kunit_iter_to_sg_kvec: ASSERTION FAILED at

Sorry about that! I wasn't aware of the large page size on powerpc.
This should fix it. I will prepare a proper patch but it would
be cool if you could verify that it actually helps.

Best regards,
Christian

diff --git a/lib/tests/kunit_iov_iter.c b/lib/tests/kunit_iov_iter.c
index 37bd6eb25896..f02f7b7aa796 100644
--- a/lib/tests/kunit_iov_iter.c
+++ b/lib/tests/kunit_iov_iter.c
@@ -1128,7 +1128,7 @@ static void __init iov_kunit_iter_to_sg_kvec(struct kunit *test)
 	struct kvec kvec;
 	size_t bufsize;
 
-	bufsize = 0x100000;
+	bufsize = 0x200000;
 	iov_kunit_iter_to_sg_init(test, bufsize, false, &data);
 
 	kvec.iov_base = data.buffer;
@@ -1146,7 +1146,7 @@ static void __init iov_kunit_iter_to_sg_bvec(struct kunit *test)
 	struct bio_vec *bvec;
 	struct iov_iter iter;
 
-	bufsize = 0x100000;
+	bufsize = 0x200000;
 	iov_kunit_iter_to_sg_init(test, bufsize, false, &data);
 
 	bvec = kunit_kmalloc_array(test, data.npages, sizeof(*bvec),
@@ -1173,7 +1173,7 @@ static void __init iov_kunit_iter_to_sg_folioq(struct kunit *test)
 	struct iov_iter iter;
 	size_t bufsize;
 
-	bufsize = 0x100000;
+	bufsize = 0x200000;
 	iov_kunit_iter_to_sg_init(test, bufsize, false, &data);
 
 	folioq = iov_kunit_create_folioq(test);
@@ -1190,7 +1190,7 @@ static void __init iov_kunit_iter_to_sg_xarray(struct kunit *test)
 	struct iov_iter iter;
 	size_t bufsize;
 
-	bufsize = 0x100000;
+	bufsize = 0x200000;
 	iov_kunit_iter_to_sg_init(test, bufsize, false, &data);
 
 	xarray = iov_kunit_create_xarray(test);
@@ -1206,7 +1206,7 @@ static void __init iov_kunit_iter_to_sg_ubuf(struct kunit *test)
 	struct iov_iter iter;
 	size_t bufsize;
 
-	bufsize = 0x100000;
+	bufsize = 0x200000;
 	iov_kunit_iter_to_sg_init(test, bufsize, true, &data);
 
 	iov_iter_ubuf(&iter, READ, data.ubuf, bufsize);