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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tariq Toukan <tariqt@nvidia.com>,
        Gal Pressman <gal@nvidia.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 03/32] net: Fix features skip in for_each_netdev_feature()
Date:   Mon, 16 May 2022 21:36:17 +0200
Message-Id: <20220516193614.877806329@linuxfoundation.org>
In-Reply-To: <20220516193614.773450018@linuxfoundation.org>
References: <20220516193614.773450018@linuxfoundation.org>
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From: Tariq Toukan <tariqt@nvidia.com>

[ Upstream commit 85db6352fc8a158a893151baa1716463d34a20d0 ]

The find_next_netdev_feature() macro gets the "remaining length",
not bit index.
Passing "bit - 1" for the following iteration is wrong as it skips
the adjacent bit. Pass "bit" instead.

Fixes: 3b89ea9c5902 ("net: Fix for_each_netdev_feature on Big endian")
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
Link: https://lore.kernel.org/r/20220504080914.1918-1-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/netdev_features.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index 2a8105d204a9..78411dc4a040 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -156,7 +156,7 @@ enum {
 #define NETIF_F_HW_TLS_TX	__NETIF_F(HW_TLS_TX)
 #define NETIF_F_HW_TLS_RX	__NETIF_F(HW_TLS_RX)
 
-/* Finds the next feature with the highest number of the range of start till 0.
+/* Finds the next feature with the highest number of the range of start-1 till 0.
  */
 static inline int find_next_netdev_feature(u64 feature, unsigned long start)
 {
@@ -175,7 +175,7 @@ static inline int find_next_netdev_feature(u64 feature, unsigned long start)
 	for ((bit) = find_next_netdev_feature((mask_addr),		\
 					      NETDEV_FEATURE_COUNT);	\
 	     (bit) >= 0;						\
-	     (bit) = find_next_netdev_feature((mask_addr), (bit) - 1))
+	     (bit) = find_next_netdev_feature((mask_addr), (bit)))
 
 /* Features valid for ethtool to change */
 /* = all defined minus driver/device-class-related */
-- 
2.35.1