[PATCH] hns3: work around stack size warning

[Arnd Bergmann]

From: Arnd Bergmann <arnd@xxxxxxxx>

The hns3 debugfs functions all use an extra on-stack buffer to store
temporary text output before copying that to the debugfs file.

In some configurations with clang, this can trigger the warning limit
for the total stack size:

 drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c:788:12: error: stack frame size (1456) exceeds limit (1280) in 'hns3_dbg_tx_queue_info' [-Werror,-Wframe-larger-than]

The problem here is that both hns3_dbg_tx_spare_info() and
hns3_dbg_tx_queue_info() have a large on-stack buffer, and clang decides
to inline them into a single function.

Annotate hns3_dbg_tx_spare_info() as noinline_for_stack to force the
behavior that gcc has, regardless of the compiler.

Ideally all the functions in here would be changed to avoid on-stack
output buffers.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
index 4e5d8bc39a1b..97dc47eeb44c 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
@@ -580,8 +580,9 @@ static const struct hns3_dbg_item tx_spare_info_items[] = {
 	{ "DMA", 17 },
 };
 
-static void hns3_dbg_tx_spare_info(struct hns3_enet_ring *ring, char *buf,
-				   int len, u32 ring_num, int *pos)
+static noinline_for_stack void
+hns3_dbg_tx_spare_info(struct hns3_enet_ring *ring, char *buf,
+			int len, u32 ring_num, int *pos)
 {
 	char data_str[ARRAY_SIZE(tx_spare_info_items)][HNS3_DBG_DATA_STR_LEN];
 	struct hns3_tx_spare *tx_spare = ring->tx_spare;
-- 
2.39.5