[PATCH] [v2] net: stmmac: selftest: avoid large stack usage

[Arnd Bergmann]

Putting a struct stmmac_rss object on the stack is a bad idea,
as it exceeds the warning limit for a stack frame on 32-bit architectures:

drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c:1221:12: error: stack 
frame size of 1208 bytes in function '__stmmac_test_l3filt' 
[-Werror,-Wframe-larger-than=]
drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c:1338:12: error: stack 
frame size of 1208 bytes in function '__stmmac_test_l4filt' 
[-Werror,-Wframe-larger-than=]

As the object is the trivial empty case, change the called function
to accept a NULL pointer to mean the same thing and remove the
large variable in the two callers.

Fixes: 4647e021193d ("net: stmmac: selftests: Add selftest for L3/L4 Filters")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
v2: simply configure function, based on feedback from Jose
---
 .../net/ethernet/stmicro/stmmac/dwxgmac2_core.c    |  5 ++---
 .../net/ethernet/stmicro/stmmac/stmmac_selftests.c | 14 ++++----------
 2 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c 
b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index d5173dd02a71..2b277b2c586b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -523,19 +523,18 @@ static int dwxgmac2_rss_configure(struct mac_device_info 
*hw,
                                  struct stmmac_rss *cfg, u32 num_rxq)
 {
        void __iomem *ioaddr = hw->pcsr;
-       u32 *key = (u32 *)cfg->key;
        int i, ret;
        u32 value;
 
        value = readl(ioaddr + XGMAC_RSS_CTRL);
-       if (!cfg->enable) {
+       if (!cfg || !cfg->enable) {
                value &= ~XGMAC_RSSE;
                writel(value, ioaddr + XGMAC_RSS_CTRL);
                return 0;
        }
 
        for (i = 0; i < (sizeof(cfg->key) / sizeof(u32)); i++) {
-               ret = dwxgmac2_rss_write_reg(ioaddr, true, i, *key++);
+               ret = dwxgmac2_rss_write_reg(ioaddr, true, i, cfg->key[i]);
                if (ret)
                        return ret;
        }
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
index c56e89e1ae56..9c8d210b2d6a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
@@ -1233,12 +1233,9 @@ static int __stmmac_test_l3filt(struct stmmac_priv 
*priv, u32 dst, u32 src,
                return -EOPNOTSUPP;
        if (!priv->dma_cap.l3l4fnum)
                return -EOPNOTSUPP;
-       if (priv->rss.enable) {
-               struct stmmac_rss rss = { .enable = false, };
-
-               stmmac_rss_configure(priv, priv->hw, &rss,
+       if (priv->rss.enable)
+               stmmac_rss_configure(priv, priv->hw, NULL,
                                     priv->plat->rx_queues_to_use);
-       }
 
        dissector = kzalloc(sizeof(*dissector), GFP_KERNEL);
        if (!dissector) {
@@ -1357,12 +1354,9 @@ static int __stmmac_test_l4filt(struct stmmac_priv 
*priv, u32 dst, u32 src,
                return -EOPNOTSUPP;
        if (!priv->dma_cap.l3l4fnum)
                return -EOPNOTSUPP;
-       if (priv->rss.enable) {
-               struct stmmac_rss rss = { .enable = false, };
-
-               stmmac_rss_configure(priv, priv->hw, &rss,
+       if (priv->rss.enable)
+               stmmac_rss_configure(priv, priv->hw, NULL,
                                     priv->plat->rx_queues_to_use);
-       }
 
        dissector = kzalloc(sizeof(*dissector), GFP_KERNEL);
        if (!dissector) {
-- 
2.20.0