netdev - [PATCH] hinic: reduce rss

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Date:   Fri, 28 Jun 2019 12:31:44 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Aviad Krawczyk <aviad.krawczyk@...wei.com>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Xue Chaojing <xuechaojing@...wei.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Zhao Chen <zhaochen6@...wei.com>,
        Eric Dumazet <edumazet@...gle.com>,
        dann frazier <dann.frazier@...onical.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] hinic: reduce rss_init stack usage

On 32-bit architectures, putting an array of 256 u32 values on the
stack uses more space than the warning limit:

drivers/net/ethernet/huawei/hinic/hinic_main.c: In function 'hinic_rss_init':
drivers/net/ethernet/huawei/hinic/hinic_main.c:286:1: error: the frame size of 1068 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

I considered changing the code to use u8 values here, since that's
all the hardware supports, but dynamically allocating the array is
a more isolated fix here.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 .../net/ethernet/huawei/hinic/hinic_main.c    | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/huawei/hinic/hinic_main.c b/drivers/net/ethernet/huawei/hinic/hinic_main.c
index 1b917543feac..ceb0e247f52d 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_main.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_main.c
@@ -256,37 +256,43 @@ static int hinic_configure_max_qnum(struct hinic_dev *nic_dev)
 
 static int hinic_rss_init(struct hinic_dev *nic_dev)
 {
-	u32 indir_tbl[HINIC_RSS_INDIR_SIZE] = { 0 };
 	u8 default_rss_key[HINIC_RSS_KEY_SIZE];
 	u8 tmpl_idx = nic_dev->rss_tmpl_idx;
+	u32 *indir_tbl;
 	int err, i;
 
+	indir_tbl = kcalloc(HINIC_RSS_INDIR_SIZE, sizeof(u32), GFP_KERNEL);
+	if (!indir_tbl)
+		return -ENOMEM;
+
 	netdev_rss_key_fill(default_rss_key, sizeof(default_rss_key));
 	for (i = 0; i < HINIC_RSS_INDIR_SIZE; i++)
 		indir_tbl[i] = ethtool_rxfh_indir_default(i, nic_dev->num_rss);
 
 	err = hinic_rss_set_template_tbl(nic_dev, tmpl_idx, default_rss_key);
 	if (err)
-		return err;
+		goto out;
 
 	err = hinic_rss_set_indir_tbl(nic_dev, tmpl_idx, indir_tbl);
 	if (err)
-		return err;
+		goto out;
 
 	err = hinic_set_rss_type(nic_dev, tmpl_idx, nic_dev->rss_type);
 	if (err)
-		return err;
+		goto out;
 
 	err = hinic_rss_set_hash_engine(nic_dev, tmpl_idx,
 					nic_dev->rss_hash_engine);
 	if (err)
-		return err;
+		goto out;
 
 	err = hinic_rss_cfg(nic_dev, 1, tmpl_idx);
 	if (err)
-		return err;
+		goto out;
 
-	return 0;
+out:
+	kfree(indir_tbl);
+	return err;
 }
 
 static void hinic_rss_deinit(struct hinic_dev *nic_dev)
-- 
2.20.0