From 50a75ac6e9f30e7fbf455be9f0d0bdf46379eb19 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 22 Sep 2020 10:12:05 +0800
Subject: [PATCH] ethtool: reduce stack usage with clang

stable inclusion
from linux-4.19.97
commit 81f7503fb41bf734bfc7ce2d38bb537d3c15214b

--------------------------------

commit 3499e87ea0413ee5b2cc028f4c8ed4d424bc7f98 upstream.

clang inlines the dev_ethtool() more aggressively than gcc does, leading
to a larger amount of used stack space:

net/core/ethtool.c:2536:24: error: stack frame size of 1216 bytes in function 'dev_ethtool' [-Werror,-Wframe-larger-than=]

Marking the sub-functions that require the most stack space as
noinline_for_stack gives us reasonable behavior on all compilers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Li Aichun <liaichun@huawei.com>
Reviewed-by:  guodeqing <geffrey.guo@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 net/core/ethtool.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 09d828a6a173..1011625a0ca4 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -2413,9 +2413,10 @@ static int ethtool_set_tunable(struct net_device *dev, void __user *useraddr)
 	return ret;
 }
 
-static int ethtool_get_per_queue_coalesce(struct net_device *dev,
-					  void __user *useraddr,
-					  struct ethtool_per_queue_op *per_queue_opt)
+static noinline_for_stack int
+ethtool_get_per_queue_coalesce(struct net_device *dev,
+			       void __user *useraddr,
+			       struct ethtool_per_queue_op *per_queue_opt)
 {
 	u32 bit;
 	int ret;
@@ -2443,9 +2444,10 @@ static int ethtool_get_per_queue_coalesce(struct net_device *dev,
 	return 0;
 }
 
-static int ethtool_set_per_queue_coalesce(struct net_device *dev,
-					  void __user *useraddr,
-					  struct ethtool_per_queue_op *per_queue_opt)
+static noinline_for_stack int
+ethtool_set_per_queue_coalesce(struct net_device *dev,
+			       void __user *useraddr,
+			       struct ethtool_per_queue_op *per_queue_opt)
 {
 	u32 bit;
 	int i, ret = 0;
@@ -2499,7 +2501,7 @@ static int ethtool_set_per_queue_coalesce(struct net_device *dev,
 	return ret;
 }
 
-static int ethtool_set_per_queue(struct net_device *dev,
+static int noinline_for_stack ethtool_set_per_queue(struct net_device *dev,
 				 void __user *useraddr, u32 sub_cmd)
 {
 	struct ethtool_per_queue_op per_queue_opt;
-- 
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