From 4b93c544e90e2b28326182d31ee008eb80e02074 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 6 Sep 2021 12:27:03 -0700
Subject: [PATCH] thunderbolt: test: split up test cases in
 tb_test_credit_alloc_all
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Git-commit: 4b93c544e90e2b28326182d31ee008eb80e02074
References: jsc#SLE-19359 jsc#SLE-20163
Patch-mainline: v5.15-rc1

The tb_test_credit_alloc_all() function had a huge number of
KUNIT_ASSERT() statements, all of which (though the magic of many many
layers of inscrutable macros) ended up allocating and initializing
various test assertion structures on the stack.

Don't do that.  The kernel stack isn't infinite, and we have compiler
warnings (now errors) for the case where a stack frame grows too large.

Like it did here, by not an inconsiderable margin:

   drivers/thunderbolt/test.c: In function ‘tb_test_credit_alloc_all’:
   drivers/thunderbolt/test.c:2367:1: error: the frame size of 4500 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
    2367 | }
         | ^

Solve this similarly to the lib/test_scanf case: split out the tests
into several smaller functions, each just testing one particular tunnel
credit allocation.

This makes the i386 allyesconfig build work for me again.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/thunderbolt/test.c | 98 +++++++++++++++++++++++++++++++-------
 1 file changed, 81 insertions(+), 17 deletions(-)

diff --git a/drivers/thunderbolt/test.c b/drivers/thunderbolt/test.c
index eca0ef311bde..1f69bab236ee 100644
--- a/drivers/thunderbolt/test.c
+++ b/drivers/thunderbolt/test.c
@@ -2206,23 +2206,13 @@ static void tb_test_credit_alloc_dma_multiple(struct kunit *test)
 	tb_tunnel_free(tunnel2);
 }
 
-static void tb_test_credit_alloc_all(struct kunit *test)
+static struct tb_tunnel *TB_TEST_PCIE_TUNNEL(struct kunit *test,
+			struct tb_switch *host, struct tb_switch *dev)
 {
-	struct tb_port *up, *down, *in, *out, *nhi, *port;
-	struct tb_tunnel *pcie_tunnel, *dp_tunnel1, *dp_tunnel2, *usb3_tunnel;
-	struct tb_tunnel *dma_tunnel1, *dma_tunnel2;
-	struct tb_switch *host, *dev;
+	struct tb_port *up, *down;
+	struct tb_tunnel *pcie_tunnel;
 	struct tb_path *path;
 
-	/*
-	 * Create PCIe, 2 x DP, USB 3.x and two DMA tunnels from host to
-	 * device. Expectation is that all these can be established with
-	 * the default credit allocation found in Intel hardware.
-	 */
-
-	host = alloc_host_usb4(test);
-	dev = alloc_dev_usb4(test, host, 0x1, true);
-
 	down = &host->ports[8];
 	up = &dev->ports[9];
 	pcie_tunnel = tb_tunnel_alloc_pci(NULL, up, down);
@@ -2243,9 +2233,18 @@ static void tb_test_credit_alloc_all(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
 	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 64U);
 
+	return pcie_tunnel;
+}
+
+static struct tb_tunnel *TB_TEST_DP_TUNNEL1(struct kunit *test,
+			struct tb_switch *host, struct tb_switch *dev)
+{
+	struct tb_port *in, *out;
+	struct tb_tunnel *dp_tunnel1;
+	struct tb_path *path;
+
 	in = &host->ports[5];
 	out = &dev->ports[13];
-
 	dp_tunnel1 = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
 	KUNIT_ASSERT_TRUE(test, dp_tunnel1 != NULL);
 	KUNIT_ASSERT_EQ(test, dp_tunnel1->npaths, (size_t)3);
@@ -2271,9 +2270,18 @@ static void tb_test_credit_alloc_all(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
 	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 1U);
 
+	return dp_tunnel1;
+}
+
+static struct tb_tunnel *TB_TEST_DP_TUNNEL2(struct kunit *test,
+			struct tb_switch *host, struct tb_switch *dev)
+{
+	struct tb_port *in, *out;
+	struct tb_tunnel *dp_tunnel2;
+	struct tb_path *path;
+
 	in = &host->ports[6];
 	out = &dev->ports[14];
-
 	dp_tunnel2 = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
 	KUNIT_ASSERT_TRUE(test, dp_tunnel2 != NULL);
 	KUNIT_ASSERT_EQ(test, dp_tunnel2->npaths, (size_t)3);
@@ -2299,6 +2307,16 @@ static void tb_test_credit_alloc_all(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
 	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 1U);
 
+	return dp_tunnel2;
+}
+
+static struct tb_tunnel *TB_TEST_USB3_TUNNEL(struct kunit *test,
+			struct tb_switch *host, struct tb_switch *dev)
+{
+	struct tb_port *up, *down;
+	struct tb_tunnel *usb3_tunnel;
+	struct tb_path *path;
+
 	down = &host->ports[12];
 	up = &dev->ports[16];
 	usb3_tunnel = tb_tunnel_alloc_usb3(NULL, up, down, 0, 0);
@@ -2319,9 +2337,18 @@ static void tb_test_credit_alloc_all(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
 	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 32U);
 
+	return usb3_tunnel;
+}
+
+static struct tb_tunnel *TB_TEST_DMA_TUNNEL1(struct kunit *test,
+			struct tb_switch *host, struct tb_switch *dev)
+{
+	struct tb_port *nhi, *port;
+	struct tb_tunnel *dma_tunnel1;
+	struct tb_path *path;
+
 	nhi = &host->ports[7];
 	port = &dev->ports[3];
-
 	dma_tunnel1 = tb_tunnel_alloc_dma(NULL, nhi, port, 8, 1, 8, 1);
 	KUNIT_ASSERT_TRUE(test, dma_tunnel1 != NULL);
 	KUNIT_ASSERT_EQ(test, dma_tunnel1->npaths, (size_t)2);
@@ -2340,6 +2367,18 @@ static void tb_test_credit_alloc_all(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
 	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 14U);
 
+	return dma_tunnel1;
+}
+
+static struct tb_tunnel *TB_TEST_DMA_TUNNEL2(struct kunit *test,
+			struct tb_switch *host, struct tb_switch *dev)
+{
+	struct tb_port *nhi, *port;
+	struct tb_tunnel *dma_tunnel2;
+	struct tb_path *path;
+
+	nhi = &host->ports[7];
+	port = &dev->ports[3];
 	dma_tunnel2 = tb_tunnel_alloc_dma(NULL, nhi, port, 9, 2, 9, 2);
 	KUNIT_ASSERT_TRUE(test, dma_tunnel2 != NULL);
 	KUNIT_ASSERT_EQ(test, dma_tunnel2->npaths, (size_t)2);
@@ -2358,6 +2397,31 @@ static void tb_test_credit_alloc_all(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
 	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 1U);
 
+	return dma_tunnel2;
+}
+
+static void tb_test_credit_alloc_all(struct kunit *test)
+{
+	struct tb_tunnel *pcie_tunnel, *dp_tunnel1, *dp_tunnel2, *usb3_tunnel;
+	struct tb_tunnel *dma_tunnel1, *dma_tunnel2;
+	struct tb_switch *host, *dev;
+
+	/*
+	 * Create PCIe, 2 x DP, USB 3.x and two DMA tunnels from host to
+	 * device. Expectation is that all these can be established with
+	 * the default credit allocation found in Intel hardware.
+	 */
+
+	host = alloc_host_usb4(test);
+	dev = alloc_dev_usb4(test, host, 0x1, true);
+
+	pcie_tunnel = TB_TEST_PCIE_TUNNEL(test, host, dev);
+	dp_tunnel1 = TB_TEST_DP_TUNNEL1(test, host, dev);
+	dp_tunnel2 = TB_TEST_DP_TUNNEL2(test, host, dev);
+	usb3_tunnel = TB_TEST_USB3_TUNNEL(test, host, dev);
+	dma_tunnel1 = TB_TEST_DMA_TUNNEL1(test, host, dev);
+	dma_tunnel2 = TB_TEST_DMA_TUNNEL2(test, host, dev);
+
 	tb_tunnel_free(dma_tunnel2);
 	tb_tunnel_free(dma_tunnel1);
 	tb_tunnel_free(usb3_tunnel);
-- 
2.26.2