diff mbox series

[v2,net-next,4/9] net: dsa: b53: serialize access to the ARL table

Message ID 20211022141616.2088304-5-vladimir.oltean@nxp.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Drop rtnl_lock from DSA .port_fdb_{add,del} | expand

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netdev/build_32bit fail Errors and warnings before: 10 this patch: 10
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netdev/verify_fixes success No Fixes tag
netdev/checkpatch warning CHECK: struct mutex definition without comment
netdev/build_allmodconfig_warn fail Errors and warnings before: 10 this patch: 10
netdev/header_inline success No static functions without inline keyword in header files

Commit Message

Vladimir Oltean Oct. 22, 2021, 2:16 p.m. UTC 
The b53 driver performs non-atomic transactions to the ARL table when
adding, deleting and reading FDB and MDB entries.

Traditionally these were all serialized by the rtnl_lock(), but now it
is possible that DSA calls ->port_fdb_add and ->port_fdb_del without
holding that lock.

So the driver must have its own serialization logic. Add a mutex and
hold it from all entry points (->port_fdb_{add,del,dump},
->port_mdb_{add,del}).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/dsa/b53/b53_common.c | 41 +++++++++++++++++++++++++++-----
 drivers/net/dsa/b53/b53_priv.h   |  1 +
 2 files changed, 36 insertions(+), 6 deletions(-)

Comments

Florian Fainelli Oct. 22, 2021, 4:32 p.m. UTC | #1 
On 10/22/21 7:16 AM, Vladimir Oltean wrote:
> The b53 driver performs non-atomic transactions to the ARL table when
> adding, deleting and reading FDB and MDB entries.
> 
> Traditionally these were all serialized by the rtnl_lock(), but now it
> is possible that DSA calls ->port_fdb_add and ->port_fdb_del without
> holding that lock.
> 
> So the driver must have its own serialization logic. Add a mutex and
> hold it from all entry points (->port_fdb_{add,del,dump},
> ->port_mdb_{add,del}).
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

Only if you need to spin a v2, small nit below:

[snip]

> +		if (ret) {
> +			mutex_unlock(&priv->arl_mutex);
>  			return ret;

I would be tempted to create an out label and have all of those tests
goto that label in case of error, just so there is a single place where
we unlock the arl_mutex.

Thanks!
--
Florian
diff mbox series

Patch

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 06279ba64cc8..22a6e3934a6f 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -1630,6 +1630,7 @@  static int b53_arl_read(struct b53_device *dev, u64 mac,
 	return -ENOENT;
 }
 
+/* Caller must hold &dev->arl_mutex */
 static int b53_arl_op(struct b53_device *dev, int op, int port,
 		      const unsigned char *addr, u16 vid, bool is_valid)
 {
@@ -1709,6 +1710,7 @@  int b53_fdb_add(struct dsa_switch *ds, int port,
 		const unsigned char *addr, u16 vid)
 {
 	struct b53_device *priv = ds->priv;
+	int ret;
 
 	/* 5325 and 5365 require some more massaging, but could
 	 * be supported eventually
@@ -1716,7 +1718,11 @@  int b53_fdb_add(struct dsa_switch *ds, int port,
 	if (is5325(priv) || is5365(priv))
 		return -EOPNOTSUPP;
 
-	return b53_arl_op(priv, 0, port, addr, vid, true);
+	mutex_lock(&priv->arl_mutex);
+	ret = b53_arl_op(priv, 0, port, addr, vid, true);
+	mutex_unlock(&priv->arl_mutex);
+
+	return ret;
 }
 EXPORT_SYMBOL(b53_fdb_add);
 
@@ -1724,8 +1730,13 @@  int b53_fdb_del(struct dsa_switch *ds, int port,
 		const unsigned char *addr, u16 vid)
 {
 	struct b53_device *priv = ds->priv;
+	int ret;
 
-	return b53_arl_op(priv, 0, port, addr, vid, false);
+	mutex_lock(&priv->arl_mutex);
+	ret = b53_arl_op(priv, 0, port, addr, vid, false);
+	mutex_unlock(&priv->arl_mutex);
+
+	return ret;
 }
 EXPORT_SYMBOL(b53_fdb_del);
 
@@ -1782,25 +1793,33 @@  int b53_fdb_dump(struct dsa_switch *ds, int port,
 	int ret;
 	u8 reg;
 
+	mutex_lock(&priv->arl_mutex);
+
 	/* Start search operation */
 	reg = ARL_SRCH_STDN;
 	b53_write8(priv, B53_ARLIO_PAGE, B53_ARL_SRCH_CTL, reg);
 
 	do {
 		ret = b53_arl_search_wait(priv);
-		if (ret)
+		if (ret) {
+			mutex_unlock(&priv->arl_mutex);
 			return ret;
+		}
 
 		b53_arl_search_rd(priv, 0, &results[0]);
 		ret = b53_fdb_copy(port, &results[0], cb, data);
-		if (ret)
+		if (ret) {
+			mutex_unlock(&priv->arl_mutex);
 			return ret;
+		}
 
 		if (priv->num_arl_bins > 2) {
 			b53_arl_search_rd(priv, 1, &results[1]);
 			ret = b53_fdb_copy(port, &results[1], cb, data);
-			if (ret)
+			if (ret) {
+				mutex_unlock(&priv->arl_mutex);
 				return ret;
+			}
 
 			if (!results[0].is_valid && !results[1].is_valid)
 				break;
@@ -1808,6 +1827,8 @@  int b53_fdb_dump(struct dsa_switch *ds, int port,
 
 	} while (count++ < b53_max_arl_entries(priv) / 2);
 
+	mutex_unlock(&priv->arl_mutex);
+
 	return 0;
 }
 EXPORT_SYMBOL(b53_fdb_dump);
@@ -1816,6 +1837,7 @@  int b53_mdb_add(struct dsa_switch *ds, int port,
 		const struct switchdev_obj_port_mdb *mdb)
 {
 	struct b53_device *priv = ds->priv;
+	int ret;
 
 	/* 5325 and 5365 require some more massaging, but could
 	 * be supported eventually
@@ -1823,7 +1845,11 @@  int b53_mdb_add(struct dsa_switch *ds, int port,
 	if (is5325(priv) || is5365(priv))
 		return -EOPNOTSUPP;
 
-	return b53_arl_op(priv, 0, port, mdb->addr, mdb->vid, true);
+	mutex_lock(&priv->arl_mutex);
+	ret = b53_arl_op(priv, 0, port, mdb->addr, mdb->vid, true);
+	mutex_unlock(&priv->arl_mutex);
+
+	return ret;
 }
 EXPORT_SYMBOL(b53_mdb_add);
 
@@ -1833,7 +1859,9 @@  int b53_mdb_del(struct dsa_switch *ds, int port,
 	struct b53_device *priv = ds->priv;
 	int ret;
 
+	mutex_lock(&priv->arl_mutex);
 	ret = b53_arl_op(priv, 0, port, mdb->addr, mdb->vid, false);
+	mutex_unlock(&priv->arl_mutex);
 	if (ret)
 		dev_err(ds->dev, "failed to delete MDB entry\n");
 
@@ -2670,6 +2698,7 @@  struct b53_device *b53_switch_alloc(struct device *base,
 
 	mutex_init(&dev->reg_mutex);
 	mutex_init(&dev->stats_mutex);
+	mutex_init(&dev->arl_mutex);
 
 	return dev;
 }
diff --git a/drivers/net/dsa/b53/b53_priv.h b/drivers/net/dsa/b53/b53_priv.h
index 544101e74bca..579da74ada64 100644
--- a/drivers/net/dsa/b53/b53_priv.h
+++ b/drivers/net/dsa/b53/b53_priv.h
@@ -107,6 +107,7 @@  struct b53_device {
 
 	struct mutex reg_mutex;
 	struct mutex stats_mutex;
+	struct mutex arl_mutex;
 	const struct b53_io_ops *ops;
 
 	/* chip specific data */