ethtool: reduce stack usage with clang

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>
[sw0312.kim: cherry-pick mainline commit 3499e87ea041 to remove frame-larger-than build warning with llvm/clang]
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: I99a8ba2db0d81a6181096ef649531e7d3fcaf3eb

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 996813f..ecb991b 100644 (file)
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -2411,9 +2411,10 @@ 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;
@@ -2441,9 +2442,10 @@ 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;
@@ -2497,7 +2499,7 @@ roll_back:
        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;