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From:   Jakob Koschel <jakobkoschel@gmail.com>
To:     "David S. Miller" <davem@davemloft.net>
Cc:     Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
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        Vladimir Oltean <vladimir.oltean@nxp.com>
Subject: [PATCH net-next v3 03/18] net: dsa: sja1105: reorder sja1105_first_entry_longer_than with memory allocation
Date:   Tue, 12 Apr 2022 14:15:42 +0200
Message-Id: <20220412121557.3553555-4-jakobkoschel@gmail.com>
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From: Vladimir Oltean <vladimir.oltean@nxp.com>

sja1105_first_entry_longer_than() does not make use of the full struct
sja1105_gate_entry *e, just of e->interval which is set from the passed
entry_time.

This means that if there is a gate conflict, we have allocated e for
nothing, just to free it later. Reorder the memory allocation and the
function call, to avoid that and simplify the error unwind path.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
---
 drivers/net/dsa/sja1105/sja1105_vl.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_vl.c b/drivers/net/dsa/sja1105/sja1105_vl.c
index 369be2ac3587..e5ea8eb9ec4e 100644
--- a/drivers/net/dsa/sja1105/sja1105_vl.c
+++ b/drivers/net/dsa/sja1105/sja1105_vl.c
@@ -36,7 +36,11 @@ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg,
 {
 	struct sja1105_gate_entry *e;
 	struct list_head *pos;
-	int rc;
+
+	pos = sja1105_first_entry_longer_than(&gating_cfg->entries,
+					      entry_time, extack);
+	if (IS_ERR(pos))
+		return PTR_ERR(pos);
 
 	e = kzalloc(sizeof(*e), GFP_KERNEL);
 	if (!e)
@@ -45,22 +49,11 @@ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg,
 	e->rule = rule;
 	e->gate_state = gate_state;
 	e->interval = entry_time;
-
-	pos = sja1105_first_entry_longer_than(&gating_cfg->entries,
-					      e->interval, extack);
-	if (IS_ERR(pos)) {
-		rc = PTR_ERR(pos);
-		goto err;
-	}
-
 	list_add(&e->list, pos->prev);
 
 	gating_cfg->num_entries++;
 
 	return 0;
-err:
-	kfree(e);
-	return rc;
 }
 
 /* The gate entries contain absolute times in their e->interval field. Convert
-- 
2.25.1