netdev - [PATCH net] net: gso_test: support CONFIG_MAX_SKB

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Date: Fri, 10 Nov 2023 10:36:00 -0500
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
	kuba@...nel.org,
	edumazet@...gle.com,
	pabeni@...hat.com,
	Willem de Bruijn <willemb@...gle.com>
Subject: [PATCH net] net: gso_test: support CONFIG_MAX_SKB_FRAGS up to 45

From: Willem de Bruijn <willemb@...gle.com>

The test allocs a single page to hold all the frag_list skbs. This
is insufficient on kernels with CONFIG_MAX_SKB_FRAGS=45, due to the
increased skb_shared_info frags[] array length.

        gso_test_func: ASSERTION FAILED at net/core/gso_test.c:210
        Expected alloc_size <= ((1UL) << 12), but
            alloc_size == 5075 (0x13d3)
            ((1UL) << 12) == 4096 (0x1000)

Simplify the logic. Just allocate a page for each frag_list skb.

Fixes: 4688ecb1385f ("net: expand skb_segment unit test with frag_list coverage")
Signed-off-by: Willem de Bruijn <willemb@...gle.com>
---
 net/core/gso_test.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/net/core/gso_test.c b/net/core/gso_test.c
index ceb684be4cbf..4c2e77bd12f4 100644
--- a/net/core/gso_test.c
+++ b/net/core/gso_test.c
@@ -180,18 +180,17 @@ static void gso_test_func(struct kunit *test)
 	}
 
 	if (tcase->frag_skbs) {
-		unsigned int total_size = 0, total_true_size = 0, alloc_size = 0;
+		unsigned int total_size = 0, total_true_size = 0;
 		struct sk_buff *frag_skb, *prev = NULL;
 
-		page = alloc_page(GFP_KERNEL);
-		KUNIT_ASSERT_NOT_NULL(test, page);
-		page_ref_add(page, tcase->nr_frag_skbs - 1);
-
 		for (i = 0; i < tcase->nr_frag_skbs; i++) {
 			unsigned int frag_size;
 
+			page = alloc_page(GFP_KERNEL);
+			KUNIT_ASSERT_NOT_NULL(test, page);
+
 			frag_size = tcase->frag_skbs[i];
-			frag_skb = build_skb(page_address(page) + alloc_size,
+			frag_skb = build_skb(page_address(page),
 					     frag_size + shinfo_size);
 			KUNIT_ASSERT_NOT_NULL(test, frag_skb);
 			__skb_put(frag_skb, frag_size);
@@ -204,11 +203,8 @@ static void gso_test_func(struct kunit *test)
 
 			total_size += frag_size;
 			total_true_size += frag_skb->truesize;
-			alloc_size += frag_size + shinfo_size;
 		}
 
-		KUNIT_ASSERT_LE(test, alloc_size, PAGE_SIZE);
-
 		skb->len += total_size;
 		skb->data_len += total_size;
 		skb->truesize += total_true_size;
-- 
2.43.0.rc0.421.g78406f8d94-goog