[dpdk-stable] patch 'net/mlx5: improve stack usage during link update' has been queued to LTS release 16.11.4

[luca.boccassi@gmail.com]

Hi,

FYI, your patch has been queued to LTS release 16.11.4

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/01/17. So please
shout if anyone has objections.

Thanks.

Kind regards,
Luca Boccassi

---
>From cf34c0a6e345b2c5d3d1a3d8a7f37646a4ec8265 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?N=C3=A9lio=20Laranjeiro?= <nelio.laranjeiro@6wind.com>
Date: Wed, 30 Aug 2017 16:47:07 +0200
Subject: [PATCH] net/mlx5: improve stack usage during link update

[ upstream commit 37a4406cdf457fb636d3bcdd0a1922fdef23f55a ]

Allocate no more memory than necessary for the second call to
ETHTOOL_GLINKSETTINGS.

Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
---
 drivers/net/mlx5/mlx5_ethdev.c | 45 +++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index 5384a880a..8ffb2d861 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -120,7 +120,6 @@ struct ethtool_link_settings {
 #define ETHTOOL_LINK_MODE_100000baseCR4_Full_BIT 38
 #define ETHTOOL_LINK_MODE_100000baseLR4_ER4_Full_BIT 39
 #endif
-#define ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32 (SCHAR_MAX)
 
 /**
  * Return private structure associated with an Ethernet device.
@@ -756,37 +755,39 @@ static int
 mlx5_link_update_unlocked_gs(struct rte_eth_dev *dev, int wait_to_complete)
 {
 	struct priv *priv = mlx5_get_priv(dev);
+	struct ethtool_link_settings gcmd = { .cmd = ETHTOOL_GLINKSETTINGS };
+	struct ifreq ifr;
+	struct rte_eth_link dev_link;
+	uint64_t sc;
+
+	(void)wait_to_complete;
+	if (priv_ifreq(priv, SIOCGIFFLAGS, &ifr)) {
+		WARN("ioctl(SIOCGIFFLAGS) failed: %s", strerror(errno));
+		return -1;
+	}
+	memset(&dev_link, 0, sizeof(dev_link));
+	dev_link.link_status = ((ifr.ifr_flags & IFF_UP) &&
+				(ifr.ifr_flags & IFF_RUNNING));
+	ifr.ifr_data = (void *)&gcmd;
+	if (priv_ifreq(priv, SIOCETHTOOL, &ifr)) {
+		DEBUG("ioctl(SIOCETHTOOL, ETHTOOL_GLINKSETTINGS) failed: %s",
+		      strerror(errno));
+		return -1;
+	}
+	gcmd.link_mode_masks_nwords = -gcmd.link_mode_masks_nwords;
+
 	alignas(struct ethtool_link_settings)
 	uint8_t data[offsetof(struct ethtool_link_settings, link_mode_masks) +
-		     sizeof(uint32_t) *
-		     ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32 * 3];
+		     sizeof(uint32_t) * gcmd.link_mode_masks_nwords * 3];
 	struct ethtool_link_settings *ecmd = (void *)data;
-	struct ifreq ifr;
-	struct rte_eth_link dev_link;
-	uint64_t sc;
 
-	(void)wait_to_complete;
-	if (priv_ifreq(priv, SIOCGIFFLAGS, &ifr)) {
-		WARN("ioctl(SIOCGIFFLAGS) failed: %s", strerror(errno));
-		return -1;
-	}
-	memset(&dev_link, 0, sizeof(dev_link));
-	dev_link.link_status = ((ifr.ifr_flags & IFF_UP) &&
-				(ifr.ifr_flags & IFF_RUNNING));
-	memset(ecmd, 0, sizeof(*ecmd));
-	ecmd->cmd = ETHTOOL_GLINKSETTINGS;
+	*ecmd = gcmd;
 	ifr.ifr_data = (void *)ecmd;
 	if (priv_ifreq(priv, SIOCETHTOOL, &ifr)) {
 		DEBUG("ioctl(SIOCETHTOOL, ETHTOOL_GLINKSETTINGS) failed: %s",
 		      strerror(errno));
 		return -1;
 	}
-	ecmd->link_mode_masks_nwords = -ecmd->link_mode_masks_nwords;
-	if (priv_ifreq(priv, SIOCETHTOOL, &ifr)) {
-		DEBUG("ioctl(SIOCETHTOOL, ETHTOOL_GLINKSETTINGS) failed: %s",
-		      strerror(errno));
-		return -1;
-	}
 	dev_link.link_speed = ecmd->speed;
 	sc = ecmd->link_mode_masks[0] |
 		((uint64_t)ecmd->link_mode_masks[1] << 32);
-- 
2.11.0