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From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <UNGLinuxDriver@microchip.com>, <davem@davemloft.net>,
        <edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
        <vladimir.oltean@nxp.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>
Subject: [PATCH net 2/5] net: lan966x: Fix usage of lan966x->mac_lock when entry is added
Date:   Thu, 14 Jul 2022 21:40:37 +0200
Message-ID: <20220714194040.231651-3-horatiu.vultur@microchip.com>
In-Reply-To: <20220714194040.231651-1-horatiu.vultur@microchip.com>
References: <20220714194040.231651-1-horatiu.vultur@microchip.com>
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To add an entry to the MAC table, it is required first to setup the
entry and then issue a command for the MAC to learn the entry.
So if it happens for two threads to add simultaneously an entry in MAC
table then it would be a race condition.
Fix this by using lan966x->mac_lock to protect the HW access.

Fixes: fc0c3fe7486f2 ("net: lan966x: Add function lan966x_mac_ip_learn()")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 drivers/net/ethernet/microchip/lan966x/lan966x_mac.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 2d2b83c03796..4f8fd5cde950 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
@@ -75,6 +75,9 @@ static int __lan966x_mac_learn(struct lan966x *lan966x, int pgid,
 			       unsigned int vid,
 			       enum macaccess_entry_type type)
 {
+	int ret;
+
+	spin_lock(&lan966x->mac_lock);
 	lan966x_mac_select(lan966x, mac, vid);
 
 	/* Issue a write command */
@@ -86,7 +89,10 @@ static int __lan966x_mac_learn(struct lan966x *lan966x, int pgid,
 	       ANA_MACACCESS_MAC_TABLE_CMD_SET(MACACCESS_CMD_LEARN),
 	       lan966x, ANA_MACACCESS);
 
-	return lan966x_mac_wait_for_completion(lan966x);
+	ret = lan966x_mac_wait_for_completion(lan966x);
+	spin_unlock(&lan966x->mac_lock);
+
+	return ret;
 }
 
 /* The mask of the front ports is encoded inside the mac parameter via a call
-- 
2.33.0